Hebrews 3:8

Harden not your hearts. That is, do not reject or neglect the merciful appeal of God’s voice (v. 7). For comment on the hardening of the heart see on Ex. 4:21; Rom. 9:18.

Provocation. Literally, “revolt,” “rebellion.” Reference here is particularly to the rebellion at Kadesh-barnea (see Num. 14:1-35), though, as Heb. 3:9 suggests, it may also apply in a general way to the various occasions when the people rebelled before the crisis at Kadesh (see Num. 14:22). There, the people refused to enter the “rest” of Canaan (see on Heb. 4:11), and as a result almost the entire adult generation was barred from entering the Promised Land (Num. 14:22-35).

Temptation. Literally, “testing,” here not “temptation” in the sense in which the word is commonly used today (see on v. 9). The “day of temptation” refers to the same event as the word “rebellion” and explains the nature of the rebellion. Israel put God to the test upon many occasions (see Ex. 17:2, 7; Num. 14:22).

The wilderness. Kadesh was situated in the Wilderness of Zin (Num. 20:1; 27:14).