Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "When Umar (may Allah be pleased with him) accepted Islam, Jibril (peace be upon him) came down and said: O Muhammad, the people of the heaven have rejoiced at Umar's acceptance of Islam."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11063