The virtue of supplication

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "All works of righteousness and goodness together are half of worship, while supplication is the remaining half. So when Allah Almighty intends good for one of His servants, He inclines his heart and makes it devoted to supplication and intimate prayer in His presence."
Imam Ahmad bin Mani' transmitted this narration; however, its chain contains Muhammad bin al-Hasan bin Abi Yazid al-Hamdani, who is a liar and matruk (abandoned), while Bakr bin Khunays is also da'if (weak), for which reason this narration is severely weak.

It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Supplication is the weapon of the believer, the pillar of the religion, and the light of the heavens and the earth."
Imam Abu Ya'la transmitted this narration in his Musnad; however, because of the severe weakness of the narrator in its chain, Muhammad bin al-Hasan bin Abi Yazid al-Hamdani, and the accusation of lying made against him by the imams of narrator criticism, the hadith scholars have declared this narration unreliable and severely weak.

It is narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Shall I not guide you to something that will save you from your enemy and bring abundance and plenty to your provision? Supplicate to Allah Almighty by night and by day, for supplication is the weapon of the believer."
Imam Abu Ya'la recorded this hadith in his Musnad; the narrator in its chain, Muhammad bin Abi Humayd, is da'if (weak).

It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that he said: One day we were present with the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Truly, the likeness of the believer is like a tree of which not even a single leaf (or a fingertip's worth) falls. Do you know which tree it is?" The Companions (may Allah be pleased with them) said: "No." He (peace and blessings be upon him) said: "It is the date palm, none of whose leaves fall; and likewise not a single supplication of the believer ever goes to waste."
Imam al-Harith bin Abi Usamah recorded this hadith in his Musnad (Bughyat al-Bahith: 3341), and the basis of the likeness of the believer to the date palm is found in Sahih al-Bukhari and Sahih Muslim.

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that he said: "Truly, the most miserly of people is the one who is miserly with the greeting of salam, and the most helpless of people is the one who is incapable of supplication." In a narration reported through another chain, it is narrated that the Messenger of Allah (peace and blessings be upon him) said the like of it, with the addition of these words: "So when you supplicate to Allah Almighty, let the young and the old among you, the blind and the eloquent (all of you) supplicate, for you do not know whose supplication among you will be granted acceptance."
Imam Abu Ya'la recorded it in his Musnad.

It is narrated from Imam al-Hasan al-Basri (may Allah have mercy on him) that he used to say: "Sometimes Allah, the Mighty and Majestic, delays the answering of a servant's supplication and grants him its reward on the Day of Resurrection, because He does not like that, in exchange for it, the servant should receive some merely temporary and passing benefit of this world."
Imam al-Harith recorded this narration in his Musnad (Bughyat al-Bahith); in its chain, al-Rabi' bin Subayh is a saduq (truthful) narrator, but there is some criticism of his memory. However, the meaning of supplication being answered and stored up for the Hereafter is established by other sahih hadith.