Numbers 10:29-33

29And Moses said to Hobab the son of Reuel the Midianite, Moses' father-in-law, "We are setting out for the place of which the Lord said, 'I will give it to you.' Come with us, and we will do good to you, for the Lord has promised good to Israel."

30But he said to him, "I will not go. I will depart to my own land and to my kindred."

31And he said, "Please do not leave us, for you know where we should camp in the wilderness, and you will serve as eyes for us.

32And if you do go with us, whatever good the Lord will do to us, the same will we do to you."

33So they set out from the mount of the Lord three days' journey. And the ark of the covenant of the Lord went before them three days' journey, to seek out a resting place for them.