Romans 9:18

So, then, He hath mercy on whom He willeth, and whom He willeth He hardeneth.

Romans 9:22-23

And what if God, willing to show forth His wrath and to make known His power, endured with much long-suffering vessels of wrath fitted for destruction;

Treasury of Scripture Knowledge

Summary

For it was of the LORD to harden their hearts, that they should come against Israel in battle, that he might destroy them utterly, and that they might have no favour, but that he might destroy them, as the LORD commanded Moses.

It was

Bible References

It was

Romans 9:18
So, then, He hath mercy on whom He willeth, and whom He willeth He hardeneth.