"Thy words were found, and I did eat them; and Thy word was unto me the joy and rejoicing of mine heart: for I am called by Thy name, O Lord God of hosts" (Jeremiah 15:16).
We have seen that there are not only two natures, but that, with their different origins, they have widely different tastes. Thus there are "the things of the flesh" and "the things of the Spirit" (Romans 8:5). Let us not forget that both these natures will be daily calling our attention to their distinctive cravings. While two different people may thrive on the same kind of food, the two natures in a Christian cannot. What feeds the old nature only starves the new; while that which is food for the new is thoroughly distasteful to the old.
We are told, therefore, to "make not provision for the flesh, to fulfil the lusts thereof" (Romans 13:14). Peter warned us to "abstain from fleshly lusts, which war against the soul" (1 Peter 2:11). On the other hand, we are exhorted, "As newborn babes, desire the sincere milk of the word, that ye may grow thereby" (1 Peter 2:2).
Let us, then, be like vigilant sentries on the watch, challenging all that we read, or think, or do, or say, with this test: Will this be food for the renewed nature, or will it minister to the flesh? Let us pursue nothing which would do the latter. May increased tenderness of conscience and distrust of self be ours, dear fellow-believer. May Christ Himself be more and more our daily food—His precious Word our constant delight.
—From The Old Nature and The New Birth by George Cutting.
Which nature is stronger? The one we feed, of course!