Hebrews 3:18

And to whom sware he that they should not enter into his
rest
As in ( Psalms 95:11 ) (See Gill on Hebrews 3:11),

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.