Musnad Ahmad 26:825

Ubaydah ibn Humayd narrated to us, from al-Mukhariq ibn Abdullah al-Ahmasi, from Tariq ibn Shihab, who said: Abdullah ibn Mas’ud said: I witnessed a scene from al-Miqdad that, had I been the one who performed it, it would have been more beloved to me than anything upon the earth. He said: He came to the Prophet, may Allah bless him and grant him peace, and he was a horseman. He said: He said, "Rejoice, O Prophet of Allah! By Allah, we will not say to you as the Children of Israel said to Moses, may Allah bless him and grant him peace: 'Go, you and your Lord, and fight; indeed, we are sitting right here.' Rather, by the One who sent you with the truth, we shall be in front of you, and to your right, and to your left, and behind you, until Allah grants you victory."