'Heart' in the Bible

Make search for the Lord, all you quiet ones of the earth, who have done what is right in his eyes; make search for righteousness and a quiet heart: it may be that you will be safely covered in the day of the Lord's wrath.

This is the town which was full of joy, living without fear of danger, saying in her heart, I am, and there is no other: how has she been made waste, a place for beasts to take their rest in! everyone who goes by her will make hisses, waving his hand.

Make melody, O daughter of Zion; give a loud cry, O Israel; be glad and let your heart be full of joy, O daughter of Jerusalem.