When I call you to go through the deep waters I will be with you! I will not let you sink nor let the waves overcome you! When you walk through the fire you will not get burned! I am the Lord thy God [paraphrase]
This is indeed true. I've seen God restore to me parts of me that I'd thought I'd lost. I've seen Him give me a new heart, a new mind. I've seen Him put new sinews into me, spiritually speaking, that weren't there before.