A black dot is dotted on the heart of a person who commits a sin…

Hadith 25:

Abu Hurairah (raa) narrated: Allah’s Messenger May peace be upon Him said :

“When a slave (a person) commits a sin (an evil deed) a black dot is dotted on his heart. Then if that person gives up that evil deed (sin), begs Allah to forgive him, and repents, then his heart is cleared (from that heart covering dot); but if he repeats the evil deed (sin), then that covering is increased till his heart is completely covered with it. And this is Ar-Ran that Allah mentioned (in the Quran),

“Nay! but on their hearts is the Ar-Ran (covering of evil deeds and sins) which they used to earn” (83:14)”

At-Tirmidhi, Vol 5 , Hadith No: 3334

Follow up a bad deed with a good one and it will wipe out the former

Hadith 7

On the authority of Abu Dhar Jundub bin Junadah, and Muadh bin Jabal that the messenger of Allah said :
“Fear Allah wherever you are, and follow up a bad deed with a good one and it will wipe it out, and behave well towards people.”

Tirmithi narrated the hadith and said it was fine, and in another version, said ture and fine

Devils and the rebels from the jinn are tied down during ramadan

Hadith 5:

Narrated Abu-Huraira (may Allah be pleased with him): ‘The Messenger of Allah (May Allah exalt his mention and protect him from imperfection) said: “When it is the first night of Ramadhan, the devils and the rebels from the jinn are tied down; the gates of the Fire are closed and no gate of them is opened but the gates of Paradise are opened and no gate of them is closed. And a caller calls: “O you who intends to do good, go ahead. O you who intend to do evil, abstain. And for Allah, there are people acquitted from the Fire every night.’” (At-Termizi)

Riyaadiss-Saliheen (The Meadows of the Righteous) (Abridged)
By Imam An Nawawi Vol. (2)
Chapiter 201, Page 803, Number 662