The writer states that the priesthood of Melchizedek is better than Aaron's priesthood and then reminds them that the priesthood of Aaron did not make anything perfect.
# this man was
"Melchizedek was"
# On one hand ... But on the other hand
These phrases are used to compare two things. Your language may have a way to emphasize that the author is making a comparison. Or you could leave out "On one hand" and translate "But on the other hand" simply as "But."
# the sons of Levi who receive the priesthood
The author says this because not all of Levi's sons became priests. AT: "the descendants of Levi who became priests" (See: [[rc://en/ta/man/translate/figs-distinguish]])
# from the people
"from the people of Israel"
# from their brothers
Here "brothers" means they are all related to each other through Abraham. AT: "from their relatives"
# they, too, have come from Abraham's body
This is a way of saying that they were descendants of Abraham. AT: "they, too, are descendants of Abraham" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The things that God promised to do for Abraham are spoken of as if they were objects that he could possess. AT: the one to whom God had spoken his promises" (See: [[rc://en/ta/man/translate/figs-metaphor]])