In the name of Allah, Most Gracious, Most Merciful.
Praise be to Allah. We seek His Help, Forgiveness and seek His refuge against the evils of ourselves and against the evils of our bad deeds. Whom Allah guides, there is no one can drive them astray and whom He misleads, no one can guide them.
I testify that there is no god but Allah alone and no partner with Him. I bear witness that Muhammad is His Servant and Messenger.
"O you who believe! Fear Allâh (by doing all that He has ordered and by abstaining from all that He has forbidden) as He should be feared. [Obey Him, be thankful to Him, and remember Him always], and die not except in a state of Islâm [as Muslims (with complete submission to Allâh)]." [Al `Imran: 102]. "O mankind! Be dutiful to your Lord, Who created you from a single person (Adam), and from him (Adam) He created his wife [Hawwâ’ (Eve)], and from them both He created many men and women; and fear Allâh through Whom you demand (your mutual rights), and (do not cut the relations of) the wombs (kinship). Surely, Allâh is Ever an All-Watcher over you." [Al Nisa': 1]. "O you who believe! Keep your duty to Allâh and fear Him, and speak (always) the truth." [Al Ahzab: 70 - 71].
To the point:
Allah (He may be Glorified) has prepared believing servants to confront all difficulties and challenges that come across their ways, retard his progress and assail their dignity and honor. Allah provided them with lethal weapon that does not vanish or end and nobody can take it away from them.
No doubt that all human, sometimes, face obstacles and difficulties, everyone resorts to the solution he finds suitable; either to physical weapon, if necessary, or others, whether to physical things for those who can't think of anything else or non-physical for those who resort to superstition. All these things may fail its people in case of dire need, unlike a believer who is not banned to use the material weapons, but Allah prevented him to rely or depend on or humble himself or prostrate to someone else. He commanded him to be dear, self-esteemed and believing. No one can remove hardship away from him but Allah and nothing can prevent good and blessings from him when Allah wills. The Prophet (peace be upon him) advises Ibn `Abbas (may Allah be pleased with him) saying: " O boy! I will instruct you in some matters. Be watchful of Allah (Commandments of Allah), He will preserve you. Safeguard His Rights, He will be ever with you. If you beg, beg of Him Alone; and if you need assistance, supplicate to Allah Alone for help. And remember that if all the people gather to benefit you, they will not be able to benefit you except that which Allah had foreordained (for you); and if all of them gather to do harm to you, they will not be able to afflict you with anything other than that which Allah had pre-destined against you. The pens had been lifted and the ink had dried up."
Therefore, the meaning of this Hadith has been embodied by men like Khabab (may Allah be pleased with him) when the infidels captured and exposed him to death and said to him: would like that Muhammad be in your place? He said: By Allah, I won't like him to be hurt with a fork in his foot.
Anyone peruses the books of history and biography, finds them full of stories of men like those. You will find there the power which Allah entrusted in the souls of those men which later was transferred to the next generation. When the Roman captured one of the next generation, it is known that a captive is the most humble person, but Islam changed those concepts and promoted in them self-esteem, even in those situations. When he saw a pigeon bemoans near him, he said:
I'm saying with a pigeon bemoaning beside me, do you know my feelings, O neighbor?
to his saying:
Would a captive laugh and a free one cries, or a distressed person keeps silent and happy man bemoans.
I should have shed tears but my tears are so dear in such situations.
Their tears were dear in events and accidents and so cheap before their Lord.
As for the weapon which Allah has provided the believers with is a spiritual weapon which is invocation. Supplicating Allah, humbling oneself before Him and the truthful resort to Him. It is a tested weapon and no one can face or take away. It is a weapon which Allah has commanded us to use in many positions of His book, Allah says: "And your Lord said: “Invoke Me, [i.e. believe in My Oneness (Islâmic Monotheism) and ask Me for anything] I will respond to your (invocation)." [Ghafir: 60]. "And when My slaves ask you (O Muhammad peace be upon him) concerning Me, then (answer them), I am indeed near (to them by My Knowledge). I respond to the invocations of the supplicant when he calls on Me (without any mediator or intercessor)." [Al Baqarah: 186]. "and ask Allâh of His Bounty." [Al Nisa': 32].
It is also narrated in the authentic Hadith which was reported in Sahih Muslim that Allah says: "all of you are hungry (needy) except one whom I feed, so beg food from Me, so that I may give that to you. O My servants, all of you are naked (need clothes) except one whom I provide garments, so beg clothes from Me, so that I should clothe you. O My servants, you commit error night and day and I am there to pardon your sins, so beg pardon from Me so that I should grant you pardon".
It is also narrated in the Hadith which was reported by Imam Ahmad, Al Tirmidhy and others in which the Prophet (peace be upon him) says: "Nothing is dearer to Allah than invocation." That is because it demonstrates needs, disability and humbleness to Allah and admission with His power. He likes His servant to show humbleness, ask for their needs and frequent complain to Him. Everyone is angry when someone asks him frequently except Allah who gets angry if you don't ask Him as it is said:
Allah gets angry when someone doesn't ask Him while human are angry when someone asks them frequently.
Anyone contemplates in the Book of Allah and the Sunnah of His Messenger, knows that invocation has a magnificent effect. Noah, Hud, Salih, Lot, and Moses supplicated their Lord to destroy those who did not believe of their people, therefore, Allah destroyed them because of those supplications.
Zakariya (peace be upon him) asks Allah for a child after he and his wife became pretty old, so Allah responded to him and gave him Yahia.
Yunus (peace be upon him) rides on a ship until it is about to sink, they voted to cast one of them into the sea, so the ship would be light. Yunus was the one chosen for this and when they cast him into the sea, a giant whale swallowed him. When he was covered by triple darkness; the darkness of the night, the darkness of the sea floor, and the darkness of the whale's belly, he supplicated His lord who knows everything. He supplicated him with heart full of faith that none can save him form this ordeal but Allah, the Lord of universe. He supplicated: "No god but You (Glory be to you), I was one of the oppressors."
Allah, the Lord of the whale, has commanded the whale to cast Yunus to the shore and commands a tree to cover him after his body was injured. Therefore, it is related in the authentic Hadith which was reported by Imam Ahmad, Al Tirmidhy and others that the Prophet (peace be upon him) says: "the supplication of Dhu Al Nun (Yunus) in the whale's belly was "no god but You (Glory be to You), I was one of the oppressors.". No one has ever supplicates Allah for anything with it but Allah responds to him." Reported by Al Hakim who added: "O Messenger of Allah, was that invocation especially for Yunus or is it for all Muslims? The Messenger (peace be upon him) says: "it is for all Muslims. Do not you listen to Allah's saying: "And thus We do deliver the believers (who believe in the Oneness of Allâh, abstain from evil and work righteousness)." [Al Anbia': 88].
Although those stories were mentioned in the Qur'an, the Sunnah also contained some stories for invocations too. The Prophet (peace be upon him) invoked Allah against the one who ate with his left hand when he instructed him to eat with the right one but the man said: I can not (out of haughty). Thereupon, the Prophet invoked Allah against him saying: I wish you could never use it, so his hand was paralyzed.
The Prophet (peace be upon him) also supplicated Allah in the Battle of Badr and other battles.
The Prophet (peace be upon him) invoked Allah to respond to some of his Companions such as Sa`d ibn Abu Waqqas, and Sa`id ibn Zayd (may Allah be pleased with them).
As for Sa`d ibn Abu Waqqas, it is reported in the two Sahih books that The People of Kufa complained against Sa‘d to ‘Umar and the latter dismissed him and appointed ‘Ammar as their chief. They lodged many complaints against Sa‘d and even they alleged that he did not pray properly. ‘Umar sent for him and said, “O Aba Ishaq! These people claim that you do not pray properly.” Abu Ishaq said, “By Allah, I used to pray with them a prayer similar to that of Allah’s Messenger (peace be upon him) and I never reduced anything of it. I used to prolong the first two Rak‘at of ‘Isha prayer and shorten the last two Rak‘at.” ‘Umar said, “O Aba Ishaq, this was what I thought about you.” And then he sent one or more persons with him to Kufa so as to ask the people about him. So they went there and did not leave any mosque without asking about him. All the people praised him till they came to the mosque of the tribe of Bani ‘Abs; one of the men called Usama ibn Qatada with a surname of Aba Sa‘da stood up and said, “As you have put us under an oath; I am bound to tell you that Sa‘d never went himself with the army and never distributed (the war booty) equally and never did justice in legal verdicts.” (On hearing it) Sa‘d said, “I pray to Allah for three things: O Allah! If this slave of yours is a liar and got up for showing off, give him a long life, increase his poverty and put him to trials.” (And so it happened). Later on when that person was asked how he was, he used to reply that he was an old man in trial as the result of Sa‘d’s curse. ‘Abdul Malik, the sub narrator, said that he had seen him afterwards and his eyebrows were over-hanging his eyes owing to old age and he used to tease and assault the small girls in the way.
As for Sa`id ibn Zayd (may Allah be pleased with him), it is reported in the two books of Sahih that Arwa bint Uways disputed with Sa`id ibn Zayd that he had seized some of the land belonging to her. She brought this dispute before Marwan ibn Al Hakam. Sa`id said: How could I take a part of her land, after what I heard from Allah's Messenger (may peace be upon him)? He (Marwan) said: What did you hear from Allah's Messenger (may peace be upon him)? He said: I heard Allah's Messenger (may peace be upon him) say: He who wrongly took a span of land would be made to wear around his neck seven earths. Marwan said: I do not ask any evidence from you after this. He (Sa`id) said: O Allah, make her blind if she has told a lie and kill her in her own land. He (the narrator) said: She did not die until she had lost her eyesight, and (one day) as she was walking in her land, she fell down into a pit and died.
In another narration, Imam Muslim reported from Muhammad ibn Zayd ibn `Abdullah ibn `Umar that he saw he blind and leaning against walls while she was walking. She said: I was inflicted with the invocation of Sa`id ibn Zayd. She passed over a well in the house she claimed to be her, fell in and it was her grave.
If someone asks: what is the benefit of invocation if what will happen is predestined for me, it will happen whether I supplicated or not. If it is not predestined for me, it will not happen whether I supplicated or not?
The answer is: there one type which we did not mention which is if the predestined matter is connected with a reason. That means: if the reason exists, the result will happen for sure and if it is not, it will not happen such as hunger and thirst or having children or not. If those things are predestined for you, they will happen whether you eat, drink or take a wife or not; is it accepted to sensible minds? You will find the answer is: they are all predestined for you when you seek the reasons to make them happen. So, you have gained them by your supplication. If you supplicate and that matter was predestined, you will be rewarded, otherwise, Allah will compensate you.