Does Abram giving Melchizedek a tithe have a special meaning? Are the bread and wine given by Melchizedek significant? I have heard Melchizedek is a type of Jesus, which makes sense if they are of the same order.
It is certainly true that Melchizedek is a type of Messiah in light of Hebrews 7. However, I would not make too much of the food items that were offered to Abram. Though some see it as a communion service, it is a bit early to have a communion service in the biblical record. That account cannot be used to teach tithing either since Abram did not tithe from his income but tithed from the spoils of war. He gave ten percent to Melchizedek and gave the rest back to the king of Sodom. Furthermore, Melchizedek was a type of Messiah but he was not a pre-incarnate Christ since every priest had to be human (Hebrews 5:1) and the Son was not human until the incarnation. Moreover, theophanies made their appearance and then disappeared after fulfilling their mission. They did not hold earthly offices such as king and priest of Jerusalem, which is what Melchizedek was. It is best just to see Melchizedek as a type of Messiah and leave it there.