The last of the Ten Commandments prohibited coveting, or developing a wrong desire for what belongs to another. (Deut. 5:21; Rom. 7:7) Jehovah gave this law to teach a valuable lesson​—his people must guard their heart, that is, their thoughts, feelings, and reasonings. He knows that wicked acts begin as wicked thoughts and feelings. King David, for example, fell into that trap. Normally, he was a good man. But on one occasion, he coveted another man’s wife. His desire led to sin. (Jas. 1:14, 15) David committed adultery, tried to deceive the woman’s husband, and then had him killed. (2 Sam. 11:2-4;12:7-11) Jehovah sees beyond a person’s outward appearance. He sees what we really are inside, in our heart. (1 Sam. 16:7) No thought, no feeling, no action can be kept secret from him. He looks for and encourages the good in us. But he wants us to identify and control wrong thoughts before they become wrong actions.​—2 Chron. 16:9; Matt. 5:27-30. w19.02 21 ¶9; 22 ¶11