Most of us or most people take supplements; a supplement is something that is added to something in order to make it complete. There are all kinds of supplements, hair loss, for losing weight; to enhance performance; to fight anxiety, and so forth.
The Bible tells us about some supplements we are to add to our faith. As followers of Jesus, we also may experience deficiency in our walk, in our faith or even in the knowledge of how to live for God in a hostile world. God has given us everything we need to continue to grow in him, but sometimes we feel we may not be growing at the rate we want, because we have not added these supplements to our faith in Jesus.