Mark 16:15-20: And He said to them, “Go into all the world and preach the gospel to every creature. He who believes and is baptized will be saved; but he who does not believe will be condemned. And these signs will follow those who believe: In My name they will cast out demons; they will speak with new tongues; they will take up serpents; and if they drink anything deadly, it will by no means hurt them; they will lay hands on the sick, and they will recover.” So then, after the Lord had spoken to them, He was received up into heaven, and sat down at the right hand of God. And they went out and preached everywhere, the Lord working with them and confirming the word through the accompanying signs. Amen.
The condition, I believe, is obedience. If we go, He’s with us. I don’t see that He’s committed Himself to be with us if we don’t go.