Hebrews 2:2

2:2 For if the message spoken through angels proved to be so firm that every violation or disobedience received its just penalty,

Hebrews 5:8

5:8 Although he was a son, he learned obedience through the things he suffered.

Hebrews 10:23

10:23 And let us hold unwaveringly to the hope that we confess, for the one who made the promise is trustworthy.