Romans chapter 4 verse 1 and Genesis chapters 14 and 15 recount the life changing decision made by Abraham to find the fullness of joy, hope and satisfication by rejecting the world, letting go of all the things he could get and resting in God Himself. Beyond all that he found he could get in this world, what he really needed was God. It was Melchizedek, a type or picture of Jesus who prepared Abraham for that fateful encounter and empowered him to make the right decision when he encountered the king of Sodom, refusing the goods of Sodom and moving ultimately forward in faith, resting in his God. Abraham believed God and it was credited to him for righteousness. Abraham was amongst the very first to enjoy the blessing of justification by faith.
Dr J Stewart Gillespie
Systematic teaching from Romans