Genesis 14--In this chapter, we see the occurrence of civil war. I call it that, because if you go back a few chapters to Genesis 10, we can see that all these warring "kings" are descendents of Noah's son Ham. Abram remains uninvolved until he receives word that Lot and his family have been taken by King Chedorloamer. At this point, he takes his own small band of fighters--some from his own house and willing neighbors--and pursues King Chedorlaomer. Even with small numbers, Abram is victorious, the offending kings slain, and all the peoples and goods (Lot's and all of Sodoms') are taken back.
Of course, now the king of Sodom shows up (the fight's over) but so does a very special visitor. Melchizedek, the King of Salem, brings sustenance and blesses Abram publicly. Abram pays Melchizedek tithes, but refuses to take Sodom's goods.
I have to admit, I don't feel like I quite have a handle on the presence of Melchizedek here, but after some study of New Testament references to this passage, I feel it is strongly suggested by the writer of Hebrews that Melchizedek was a Theophany. He is called the King of Salem, which means peace, and Christ is also called the Prince of Peace in the prophecy of Isaiah 9:6. He is introduced as a priest of the most high God at a time when the hierarchy of religious leadership for the Hebrew people has yet to be established--far from it, with Isaac still just a twinkle in Abram's eye. Finally, Abram paid Melchizedek tithes. This honor of first fruits is owed to God alone. In any case, Abram definitely understood this King to be from the God who had been speaking to Him all of these years.
Though still not transformed, Abram's morality continues to be evident. He is loyal to a disloyal family member. He is brave enough to pursue danger with risk of great personal cost based on the principles of family. He shows respect and homage to the priest of God through tithes. He refuses the spoils of Sodom for himself, but makes provision for those who fought beside him. His heart was in the right place for God to reveal himself to Abram, and to transform him into that new creature!
Abram's continued morality, though not yet "transformed." He has been shown the truth repeatedly, but it is not until the next chapter that he believes the truth and it's counted unto him as righteousness.