The phrase "Upright in Heart" refers to the godly person being one who is unbending and standing straight up for the Lord and for His Word. Straight up in their lives, unbending in their convictions, unwavering in their Christian conduct and faith. Josh. 1:7 "Only be thou strong and very courageous, that thou mayest observe to do according to all the law, which Moses my servant commanded thee: turn not from it to the right hand or to the left, that thou mayest prosper whithersoever thou goest."