As children grow physically, they learn to eat solid food that gives them strength and vitality. In the same way, every believer needs to take on the responsibility to feed himself on solid spiritual food. To fail to do this is to remain spiritually weak and undernourished. You can roughly tell the physical age of people by how they look. Their spiritual age is revealed by their ability to distinguish good from evil and by their personal character that's shown day by day. Apply yourself to the Scriptures and the Scriptures to yourself.