en_tn/heb/03/08.md

do not harden your hearts

Here "hearts" is a metonym for a person's mind. The phrase "harden your hearts" is a metaphor for being stubborn. AT: "do not be stubborn" or "do not refuse to listen" (See: rc://en/ta/man/translate/figs-metonymy)

as in the rebellion, in the time of testing in the wilderness

Here "rebellion" and "testing" can be stated as verbs. AT: "as when your ancestors rebelled against God and tested him in the wilderness" (See: rc://en/ta/man/translate/figs-abstractnouns)