'Hearts' in the Bible

But as we were allowed of God to be put in trust with the gospel, even so we speak; not as pleasing men, but God, which trieth our hearts.

And for this further reason we render unceasing thanks to God, that when you received God's Message from our lips, it was as no mere message from men that you embraced it, but as--what it really is--God's Message, which also does its work in the hearts of you who believe.

To the end he may stablish your hearts unblameable in holiness before God, even our Father, at the coming of our Lord Jesus Christ with all his saints.

Therefore a defiant spirit in such a case provokes not man but God, who puts His Holy Spirit into your hearts.