It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "There is no contagion (that spreads by itself without the command of Allah), no ill omen in the month of Safar, no hamah (it has no reality), and two months are not (both) completed (together); and whoever breaks a pledge of protection (a covenant) will not even smell the fragrance of Paradise."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7730