Du'a bidding farewell to someone

Hadith on Farewell: I leave you to the protection of Allah.
Salim reported: Ibn Umar, may Allah be pleased with him, would say to a man if he intended to travel, “I bid you farewell as the Messenger of Allah, peace and blessings be upon him, would bid farewell. The Prophet would say: I leave you under the protection of Allah in your religion, your trusts, and your final deeds.”
(Sunan al-Tirmidhī 3443)