For it was of the Lord to harden their hearts
 As he hardened the hearts of Pharaoh and the Egyptians, that his power might be displayed in their destruction: 
 that they should come against Israel battle;
 and so fall in it: 
 that he might destroy them utterly;
 for their abominable wickedness, idolatry, incest they had been guilty of: 
 [and] that they might have no favour;
 which they would have had, had they made peace as the Gibeonites did; or that they might not pray and make supplication, the Lord not giving them a spirit of supplication, but an hard heart, as Gussetius F6 observes the words may be interpreted, though he seems to prefer the former, sense: 
 but that he might destroy them, as the Lord commanded Moses;
 ( Deuteronomy 7:1 Deuteronomy 7:2 ) . 
The Brenton translation of the Septuagint is in the public domain.