Aswad (may Allah have mercy on him) says that I heard a man asking Sayyiduna Ibn Mas'ud (may Allah be pleased with him): "Did the Prophet (peace and blessings be upon him) return after prayer from the right side or the left side?" He replied: "The Prophet (peace and blessings be upon him) would return from whichever side he wished, and most often he would return from the left side towards his chambers."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 4383
Hadith Gradingحکم دارالسلام:صحيح، وهذا إسناد حسن من أجل ابن إسحاق.