Chief of sinners though I be,
Christ is All in all to me;
All my wants to Him are known,
All my sorrows are His own.
Safe with Him from earthly strife,
He sustains the hidden life.
The last two lines intrigue me. I think I understand the second to last line to mean that as long as we have a relationship with Jesus, He will provide us with relief from the worries and cares that would consume us.
But for a hymn to refer to "the hidden life" -- I can't quite grasp it. I can't think that it would mean that God wants us to take our most base thoughts and desires and somehow "sustain" them, that is, to keep them as part of our identity.
Maybe "the hidden life" is just referring to the intangible aspects of life in general: thoughts, worries, fears. If we gave ourselves over to our darkest thoughts and fears, we would pretty much self-destruct. Maybe it means that God gives us strength to conquer our fears and to live lives with peaceful hearts.
This hymn also has a great closing verse:
O my Savior, help afford
By Thy Spirit and Thy Word!
When my wayward heart would stray,
Keep me in the narrow way;
Grace in time of need supply
While I live and when I die.