Sahih Bukhari

Allah's Messenger (ﷺ) said, "For every prophet there is one (special invocation (that will not be rejected) with which he appeals (to Allah), and I want to keep such an invocation for interceding for my followers in the Hereafter."

that the Prophet (ﷺ) said, "For every prophet there is an invocation that surely will be responded by Allah," (or said), "For every prophet there was an invocation with which he appealed to Allah, and his invocation was accepted (in his lifetime), but I kept my (this special) invocation to intercede for my followers on the Day of Resurrection."

The Prophet (ﷺ) said "The most superior way of asking for forgiveness from Allah is: 'Allahumma anta Rabbi la ilaha illa anta, Anta Khalaqtani wa ana `Abduka, wa ana 'ala ahdika wa wa'dika mastata'tu, A`udhu bika min Sharri ma sana'tu, Abu 'u Laka bini'matika 'alaiya, wa Abu 'u laka bidhanbi faghfir lee fa innahu la yaghfiru adhdhunuba illa anta." The Prophet (ﷺ) added. "If somebody recites it during the day with firm faith in it, and dies on the same day before the evening, he will be from the people of Paradise; and if somebody recites it at night with firm faith in it, and dies before the morning, he will be from the people of Paradise."

I heard Allah's Messenger (ﷺ) saying." By Allah! I ask for forgiveness from Allah and turn to Him in repentance more than seventy times a day."

`Abdullah bin Mas`ud related to us two narrations: One from the Prophet (ﷺ) and the other from himself, saying: A believer sees his sins as if he were sitting under a mountain which, he is afraid, may fall on him; whereas the wicked person considers his sins as flies passing over his nose and he just drives them away like this." Abu Shihab (the sub-narrator) moved his hand over his nose in illustration. (Ibn Mas`ud added): Allah's Messenger (ﷺ) said, "Allah is more pleased with the repentance of His slave than a man who encamps at a place where his life is jeopardized, but he has his riding beast carrying his food and water. He then rests his head and sleeps for a short while and wakes to find his riding beast gone. (He starts looking for it) and suffers from severe heat and thirst or what Allah wished (him to suffer from). He then says, 'I will go back to my place.' He returns and sleeps again, and then (getting up), he raises his head to find his riding beast standing beside him."

Allah's Messenger (ﷺ) said, "Allah is more pleased with the repentance of His slave than anyone of you is pleased with finding his camel which he had lost in the desert. "