Consider how our physical health illustrates the importance of who we are on the inside. First, to keep ourselves in good condition on the inside, we must choose a healthy diet, and we need to exercise regularly. Likewise, to keep ourselves in good spiritual condition, we must choose a healthy diet of spiritual food and regularly exercise our faith in Jehovah. That form of exercise involves applying what we learn and speaking about our faith. (Rom. 10:8-10; Jas. 2:26) Second, based on outward appearance, we might think that we are healthy even though we are actually diseased on the inside. In a similar way, based on our theocratic routine, we may think that our faith is strong, but wrong desires could be growing in us. (1 Cor. 10:12; Jas. 1:14, 15) We must remember that Satan would like to infect us with his thinking. w19.01 15 ¶4-5