Praise of men

I was listening to a sermon by John Piper about fasting--he was sharing about the passage which says that we should not anounce our fasting to the world to prove that we are more spiritual. Fasting becomes a hypocritical act if it is done for the audience of others because it proves that we are hungering for acceptance from others rather than the praise of the One. This applies not only to fasting but to every good thing we do in the world.