It is narrated from Sayyiduna Sunabih (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "My Ummah will remain firmly holding on to its religion as long as they do not wait for the stars to cluster in the Maghrib prayer, in imitation of the Jews, and as long as they do not delay the Fajr prayer, in imitation of the Christians."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7387