Hadis-e-Pak
"Jis shaks ne Emaan k sath sawab hasil karne ki niyat se Aitikaf kia
Us k tamam pichle gunah baksh diye jaye'n ge ... "
Ibn Abbas narrated that Rasulullah (saw) said:
This person’s sins who is in I’tikaf are confined and deeds are written into his book as if he is doing them. (Ibn majah, Jamu’l Fawaid)
The persons who secludes himself (in the Masjid in I’tikaf) in true faith and hope (for the reward of Allah), all of his previous sins shall be forgiven.” (Kanzul Ummal, Hadith 24007)