Paul is saying that it is impossible to be truly justified at conversion without God looking after us right into heaven. Conversion isn’t a fresh start. Conversion, authentic regeneration, is the invincibilizing of our future. We were enemies when God came to us and justified us; how much more will God care for us now that we are friends—indeed, sons? As John Flavel put it, “As God did not at first choose you because you were high, he will not now forsake you because you are low.”
