Stephen Cook has an interesting post on Melchizedek (Gen 14:17-24). He suggests that Melchizedek's non-Hebrew origins highlights a universal theme. Cook writes,
A great triangle of blessing begins here to connect Abraham's people and the world. Abraham has blessed a mass of non-Hebrews (Melchizedek's people) by ridding Canaan of predators (vv. 1-16). But God's blessing now (vv. 17-24) flows mysteriously back to Abraham through a non-Hebrew channel!