John Gill

For their rock is not as our rock,.... That is, the gods of the Heathens, the rock in which they trusted, are not like the God of Israel, the rock of salvation, in which all true believers, whether Jews or Gentiles, place their confidence; and indeed let that be what it will, that is short of Christ the rock, men lay the stress of their salvation on, it is no rock, but sand, and will stand them in no stead; see Mat 7:24, even our enemies themselves being judges; as has been confessed of the God of Israel by the Heathens; see Exo 14:25; and was by Titus with respect to the destruction of Jerusalem; See Gill on Deu 32:27; and by the Roman emperors when conquered by the Christians, who asked pardon of the God of the Christians, and owned that the God of Constantine was the true God; See Gill on Rev 6:16.