Promises that come with Actions

Psalm 31:24

Be of good courage, and he shall strengthen your heart,

all ye that hope in the LORD.

This is an awesome promise.  I know that God keeps His promises.  He will give strength to a weary, fainting heart.  But it is reliant on my actions - taking courage and hoping in Him ... that is the hard part.  It is easy to spout in theory, but hard to practice.