It is narrated from Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him); he said: The Messenger of Allah (peace and blessings be upon him) said: "Setting out in the path of Allah for one morning or one evening is better than everything upon which the sun rises and sets."
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 4064