I change, He changes not;
The Christ can never die;
His love, not mine, the resting-place,
His truth, not mine, the tie.
Horatius Bonar, I Hear the Words of Love
This is the same truth Piper said here, and Lloyd-Jones said here. Horatius Bonar simply put it in verse. This truth is critically important for every Christian to understand and believe. It will never do any good as a theory.
They looked to Him and were radiant, and their faces will never be ashamed. (Psalm 34:5)