Mr. Chambers comments that "My say-so is to be built on God's say-so. God says - 'I will never leave thee,' then I can with good courage say - 'The Lord is my helper, I will not fear' - I will not be haunted by apprehension."
To haunt means to come to mind continuously, to pursue relentlessly, to harass. Apprehension means to be fearful or have uneasy anticipation of the future; to dread.
In obedience to God's Word, followers of Jesus Christ can experience a life of freedom and emancipation from fear and doubt. Jesus did not do anything apart from His Father's say-so and we, as believers, are to do (practice) the same!