Charles John EllicottXXVII.(1) Boast not thyself of to-morrow.—This is forbidden also in James 4:13, sqq.; but there on the higher ground that it argues a want of submission to the will of Almighty God. This temper of mind, as well as the opposite one of too great anxiety for the morrow (Matthew 6:34), proceed from the same cause, too much dependence upon self, and are only to be met by learning to realise the love of God for His children (ibid., 26, 30, 33), and looking up to Him daily for protection, guidance,... read more
E.W. Bullinger's Companion Bible Notes - Proverbs 27:1
Boast not, &c. Compare James 4:13-16 . thyself . . . thou. Second person. thou knowest not. Illustrations: Jonathan (1 Samuel 23:17 . Compare Proverbs 31:2 ); Abner (2 Samuel 3:9 , 2 Samuel 3:10 . Compare Proverbs 3:27 ); Ben-hadad (1 Kings 20:3-31 . Compare Proverbs 27:11 ); Ahab (1 Kings 22:26 , 1 Kings 22:27 , 1 Kings 22:34-37 ); Haman (Esther 5:12 ; Esther 7:1 , Esther 7:10 ); Nebuchadnezzar (Daniel 4:30 , Daniel 4:31-33 ); the rich fool (Luke 12:20 ). read more