Tied-up Joys

I am always being tempted to tie my joys to changing circumstances instead of to my unchanging God.
In happy times I am tempted to wrap my heart around the present joys - nervously, knowing that they may be snatched away at any time.
In hard times, I often find my joys nearly drowned, as if they had been tied to a rock, only to have the rock thrown into a dark and turbulent ocean.
What then am I to do? I must continually be aiming, in every situation, with the help of God, to wrap up all my joys in Christ, and in His love and His will - to tie them fast to Him and keep them there, come what may. He does not change; He lives forever, no longer able to be touched by the power of death. Joys tied here cannot be moved, and here I find the secret of contentment