Al-Mu'jam al-Awsat 2318 — the Messenger of Allah ﷺ said to him: O boy!

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said to him: "O boy! Shall I not give you a gift? Shall I not bestow something on you? Shall I not grant you something?" He says: I said: "Yes, O Messenger of Allah! May my father and mother be sacrificed for you." He says: I thought that he (peace and blessings be upon him) would grant me some portion of wealth, but he (peace and blessings be upon him) said: "Four rak'ahs which you should pray every day; if you are not able to do so daily, then every Friday; if you cannot do that, then once every month; if you cannot do that, then once every year; and if you cannot do that, then once in your lifetime. (The method is that) you say the takbir, then recite Surah al-Fatihah and another surah, then say fifteen times: 'Subhan Allah, wal-hamdu lillah, wa la ilaha illa Allah, wa Allahu akbar' (Glory be to Allah, all praise is for Allah, there is no god but Allah, and Allah is the Greatest). Then bow and say it ten times, then raise your head from bowing and say it ten times, then prostrate and say it ten times, then raise your head from the prostration and say it ten times, then prostrate (the second time) and say it ten times, then raise your head and say it ten times. Then do the same throughout your whole prayer. When you are about to finish (the prayer), after the tashahhud and before the salam, make this supplication: 'Allahumma inni as'aluka tawfiqa ahl al-huda, wa a'mala ahl al-yaqin, wa munasahata ahl al-tawbah, wa 'azma ahl al-sabr, wa jidda ahl al-hisbah, wa talaba ahl al-raghbah, wa ta'abbuda ahl al-wara', wa 'irfana ahl al-'ilm hatta akhafak. Allahumma as'aluka makhafatan tahjizuni 'an ma'asik, hatta a'mala bi-ta'atika 'amalan astahiqqu bihi ridak, wa hatta unasihaka fi al-tawbati khawfan mink, wa hatta ukhlisa laka al-nasihata hubban lak, wa hatta atawakkala 'alayka fi al-umuri husna zannin bik, subhana khaliq al-nar' (O Allah! I ask You for the success granted to the people of guidance, the deeds of the people of certainty, the sincerity of the people of repentance, the resolve of the people of patience, the effort of those who seek reward, the seeking of the people of eager longing, the worship of the people of scrupulous piety, and the understanding of the people of knowledge, until I come to fear You. O Allah! I ask You for a fear that restrains me from disobeying You, so that I may do such deeds in obedience to You by which I become deserving of Your pleasure, and so that I remain sincere in repentance out of fear of You, remain sincere in my goodwill towards You out of love for You, and rely on You in all matters, having a good opinion of You. Glory be to the Creator of the Fire).
O Ibn Abbas! When you do this, Allah will forgive your sins: the small and the great, the old and the new, the hidden and the open, those done deliberately and those done by mistake."
Imam al-Tabarani (may Allah have mercy on him) said: "Only Abd al-Quddus narrated this hadith from Mujahid (may Allah have mercy on him), and only Musa bin Ja'far from Abd al-Quddus, and Abu al-Walid al-Makhzumi is alone in narrating it."