The wicked man flees though no-one pursues, but the righteous are as bold as a lion (v1).
A guilt ridden conscious is a terrible master.
Leviticus 26 records some of the consequences of disobedience to God's commands; one of these being 'the sound of a windblown leaf will put them to flight'.
In stark contrast to this is David's declaration as he faces Goliath in 1Sam17 "Today I will strike you down and cut off your head". Not much evidence of a desire to flee.
One can only conclude that 'guilt' robs courage whilst a 'clean heart' fuels it.
If we are lacking courage for obedience (or to stand and fight), confessing our sins to Jesus and enjoying again His righteousness would be a good starting point.