Why, O Lord, do You cause us to stray from Your ways
And harden our heart from fearing You?
Return for the sake of Your servants, the tribes of Your heritage (Is 63:17).
God causes men to stray from His ways. Wait a second, “Doesn’t God desire not the death of the sinner but that all may come to repentance?” Well, He does, but He also desires that the wicked are punished and that vessels of mercy can see what they are spared from. This is why He hardened the Pharaoh. So, God is not compelled to show all mercy, and as just punishment for sin He gives sinners over to the hardness of their own hearts.
Lastly, though this may be stretching it a bit, the final phrase in the verse is probably a prayer in light of what was just said. Isaiah is asking that God stop hardening their hearts and stop allowing them to stray. So, what point would such a prayer have if the Holy Spirit cannot positively affect the will of a man?
Either way you dice it, you cannot deny the Scripture is monergistic.