Hebrews 7:5

7:5 And those of the sons of Levi who receive the priestly office have authorization according to the law to collect a tithe from the people, that is, from their fellow countrymen, although they too are descendants of Abraham.

Hebrews 11:11

11:11 By faith, even though Sarah herself was barren and he was too old, he received the ability to procreate, because he regarded the one who had given the promise to be trustworthy.