"The Messenger of Allah said: 'No one of you disputes more intensely for something that is rightly his in this world, than the believers will dispute with their Lord for their brothers who have entered the Fire. They will say: 'Our Lord, our brothers used to pray with us and fast with us, and perform Hajj with us, and you have caused them to enter the Fire?' He will say: 'Go and bring forth whomever you recognize among them.' So they will go to them, and will recognize them by their appearances. Among them will be those who have been seized by the Fire up to the middle of their shins, and some among them those whom it has taken up to his ankles. They will bring them forth, then they will say: 'Our Lord, we have brought forth those whom You commanded us (to bring forth).' He will say: 'Bring forth everyone in whose heart is faith the weight of a Dinar.' Then He will say: 'Everyone in whose heart is faith the weight of half a Dinar,' until He will say: 'In whose heart is faith the weight of the smallest speck.'" Abu Sa'eed said: "Whoever does not believe this, let him read the Verse: 'Verily, Allah forgives not that partners should be set up with Him (in worship), but He forgives except that (anything else) to whom He wills up to a tremendous (sin).'"
Sunan an-Nasa'i Book 47, Hadith 26
The Prophet said: "The best of prayers for forgiveness is for a person to say: 'Allahumma, anta rabbi, la ilaha illa anta, khalaqtani wa ana 'abduka, wa ana 'ala 'ahdika wa wa'dika mastata'tu, a'udhu bika min sharri ma sana'tu, abuw'u laka bidhanbi, wa abuw'u laka bini'matika 'alayya faghfirli, fa innahu la yaghfirudh-dhunuba illa anta (O Allah, You are my Lord, there is no god but You. You have created me and I am Your slave and I am keeping my promise and covenant to You as much as I can. I seek refuge with You from the evil of what I do. I acknowledge Your blessing and I acknowledge my sin, so forgive me, for there is none who can forgive sin except You.)' If he says this in the morning, believing in it firmly, and dies on that day before evening comes, he will enter Paradise, and if he says it in the evening, believing firmly in it, and dies before morning comes, he will enter Paradise." Al-Walid bin Tha'labah contradicted him.
Sunan an-Nasa'i Book 50, Hadith 95
`Abdullah;- performed the Hajj and we reached Al-Muzdalifa at or about the time of the `Isha' prayer.
He ordered a man to pronounce the Adhan and Iqama and then he offered the Maghrib prayer and
offered two rak`at after it. Then he asked for his supper and took it, and then, I think, he ordered a
man to pronounce the Adhan and Iqama (for the `Isha' prayer). (`Amr, a sub-narrator said: The
intervening statement 'I think', was said by the sub-narrator Zuhair) (i.e. not by `Abdur-Rahman).
Then `Abdullah offered two rak`at of `Isha' prayer. When the day dawned, `Abdullah said, "The
Prophet never offered any prayer at this hour except this prayer at this time and at this place and on
this day." `Abdullah added, "These two prayers are shifted from their actual times -- the Maghrib
prayer (is offered) when the people reached Al-Muzdalifa and the Fajr (morning) prayer at the early
dawn." `Abdullah added, "I saw the Prophet (ﷺ) doing that."
Sahih al-Bukhari Book 25, Hadith 155