Silsilat al-Ahadith al-Sahihah

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When any one of you arrives at a gathering, he should greet with salam, and when he gets up to leave, he should also greet with salam, because the first salam is not superior to the second (rather, both are equally important)."