Musannaf Ibn Abi Shaybah 12152 — Those who used to come to the grave

Nafi' says that whenever Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) intended to set out (on a journey), he would enter the Mosque of the Prophet (peace and blessings be upon him) and pray, then come to the grave of the Messenger and offer salam in these words: 'As-salamu alayka ya Rasulallah, as-salamu alayka ya Aba Bakr, as-salamu alayka ya abatah' (Peace be upon you, O Messenger of Allah; peace be upon you, O Abu Bakr; peace be upon you, O my father). Then he would set off on his way. Likewise, when he returned from a journey, he would come to the mosque and do this before entering his house.