4  …Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God. 

Jesus is using a natural human idea to convey a spiritual thought. He’s saying to us that what bread (or food) is to the body, the Word of God is to the spirit, or the heart, of man. 

You know that if you eat food regularly, it will build you up physically. Yet if you eat right but don’t exercise, all you’ll do is get flabby and out of shape.

In much the same way, you need to feed your faith on God’s Word. But you also need to exercise your faith, because if you don’t, your faith muscles will be flabby. They won’t be able to do much spiritually when it comes to moving mountains in your life.

You can feed your spirit on God’s Word and thereby feed your faith, because God’s Word is faith food. But you also need to exercise your faith to develop it and cause it to grow.

In Romans 10:8, Paul called the message he preached the word of faith. He called the Word of God the word of faith, because the Word will cause faith to come into your heart (Rom. 10:17). God’s Word will build assurance, confidence, and faith in your heart. Then you’re to exercise that faith.

So we know that the measure of faith we’ve received can be increased by doing two things: by feeding it on God’s Word and by putting it into practice (or exercising it) in everyday living.

One person said, “You either have faith or you don’t.” In one sense, that’s true. You’re either a believer or a non-believer. But in another sense when people say that, they are implying that every believer has faith in every respect the same as another believer. But that’s not true. One person’s faith may not be the same as another person’s faith. There can be a measurable difference! You see, the Word of God tells us that our faith can grow. Therefore, one person’s faith may not be as developed or as strong as another person’s faith.

Remember, it’s up to you what you do with the measure of faith God has given you. For example, you can cause your faith to grow. You can feed and exercise it so when the storms of life come, you will have strong faith. But another person may not do anything with his faith. The person who does nothing with his faith will have weak faith.

Second Thessalonians 1:3 says, “We are bound to thank God always for you, brethren, as it is meet, because that your FAITH GROWETH EXCEEDINGLY. . . .” God is saying that faith can grow. Well, since faith can grow, it can be either strong or weak—developed or undeveloped.