John 6:56-58

It is said of a certain little insect that it always exhibits the color of the leaf on which it feeds. So it is exactly with the Christian. It is very easy to tell what we are feeding upon.
Nature to the mind attentive, teaches oft a hidden truth, Even by a tiny insect, speaking to our hearts reproof. Many a different plant will furnish daily food the insect needs,
But it always takes the color from the leaf whereon it feeds.
Christians from the bread of heaven ofttimes turn to earthly fare,
But a tell-tale change of color to their shame they always bear.
If on Christ the. Lamb we're feeding, we'll present a heavenly blue,
But the taste of earthly follies changeth to another hue.