Hebrews 3:18
Ver. 18. And to whom sware he that they should not enter into his rest,.... As in Ps 95:11, but to them that believed not? the Lord; notwithstanding the signs and wonders he showed among them, they would not be persuaded by Moses and Aaron, by Joshua and Caleb, to be still and quiet, to cease murmuring, and submit to the will of God, and believe in him; they were disobedient, stubborn, and rebellious, and would go up, when they were bid not to go up; for which reason God swore in his wrath that they should not enter into the good land. Unbelief is a source of sin, and cause of judgment, being greatly provoking to God. Hebrews 3:19Ver. 19. So we see that they could not enter in,.... To God's rest, the land of Canaan, for they died by the plague before the Lord, and their carcasses fell in the wilderness, before they came to it, Nu 14:37 and the reason was,because of unbelief; their distrust of God, his power, and his providence; this instance is produced by the apostle, to show the evil nature of unbelief, and the sad effects of it; to deter persons from it, and that they might take heed of encouraging it; and which instance he further improves in the following chapter.
John Gill's Exposition of the Entire Bible.