Musnad Ahmad 25:864

Ishaq narrated to us, Abu al-Ahwas narrated to us, from Simak ibn Harb, from Ikrimah, from Ibn Abbas, who said: When the Messenger of Allah (peace and blessings of Allah be upon him) intended to set out on a journey, he would say: "O Allah, You are the Companion in the journey and the Successor in the family. O Allah, I seek refuge in You from the hardship of the journey and the gloom of the return. O Allah, shorten the earth for us and make the journey easy for us."