It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever enters ihram from Bayt al-Maqdis (Jerusalem), his past sins are forgiven."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20151