Sayyiduna Ka'b bin Malik (may Allah be pleased with him) used to say: When the Messenger of Allah (peace and blessings be upon him) returned from a journey, he would go to the mosque, pray two rak'ahs in it, and then sit for the people, for their questions and their requests for fatwas.
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16158