Numbers 14:23

14:23 they will by no means ¹  see the land that I swore to their fathers, nor will any of them who despised me see it.

Hebrews 3:11

3:11 “As I swore in my anger, ‘They will never enter my rest!’” ² 

[14:23]  ¹ tn The word אִם (’im) indicates a negative oath formula: “if” means “they will not.” It is elliptical. In a human oath one would be saying: “The Lord do to me if they see…,” meaning “they will by no means see.” Here God is swearing that they will not see the land.

[3:11]  ² tn Grk “if they shall enter my rest,” a Hebrew idiom expressing an oath that something will certainly not happen.