Sayyiduna Ali (may Allah be pleased with him) said: "Whoever wishes to see the face of the Messenger of Allah (peace and blessings be upon him) from the head to the neck, let him look at al-Hasan; and whoever wishes to see what is below the neck, let him look at al-Husayn. The two of them have divided it between themselves."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2756