For of course it is not angels but descendants of Abraham that He is to help.

For God who promised to Abraham, since he had none greater to swear by, swore by himself,

And so by patiently waiting, Abraham obtained the promise.

Since God wanted to show conclusively to those who would inherit the promise [i.e., Abraham and all of his spiritual descendants], how unchangeable His purpose was, He confirmed it with an oath.

For this Melchizedek, king of Salem, priest of God Most High, having met Abraham returning from the slaughter of the kings, also blessed him.

To whom also Abraham divided a tenth of all. Being actually translated, first, king of righteousness, and then also, king of Salem, which is king of peace,

And notice how great this man was, to whom also the patriarch Abraham gave a tenth out of the best spoils.

Now indeed those of the sons of Levi who receive the priesthood have commandment to collect tithes from the people according to the law, that is, of their brothers, although having come out of the loins of Abraham.

But the man who did not descend from them has received tithes from Abraham, and has blessed the man having the promises.

And, so to speak, Levi also, the man who receives tithes, has paid tithes through Abraham,

for Levi was yet in the loins of his father, when Melchizedek met Abraham.

By faith Abraham, when he was called, obeyed to go out unto a place which he was to receive for an inheritance; and he went out, not knowing whither he went.

By [having] faith, Sarah herself received the ability to have children, even though she was [sterile, being] past the age of child-bearing, since she considered God faithful to His promise. [Note: Some translations consider "Abraham" to be the subject of this highly controversial verse. See Lightfoot, pages 222-225].

Therefore, from one man [Abraham], who was as good as dead [i.e., because of having a sterile wife], were born descendants as numerous as the stars in the sky and as countless as the [grains of] sand on the seashore.

But the truth is that they were longing for a better country, that is, a heavenly one. For that reason God is not ashamed [of them or] to be called their God [even to be surnamed their God—the God of Abraham, Isaac, and Jacob]; for He has prepared a city for them.

By faith Abraham, being tried, offered up Isaac: yea, he that had gladly received the promises was offering up his only begotten'son ;

Abraham was certain that God could raise the dead, and figuratively speaking, he did get Isaac back in this way.