Create in me a pure heart, O God, and renew a steadfast spirit within me. Psalm 51.10
I still remember the relief, after weeks of living "in the field" on military service, alternating between two sets of clothes (wet and dry routine), of finally being able to bathe and put on a fresh outfit. I felt like a new man!
In this Psalm, David describes how his misdemeanours have left him feeling utterly filthy, inside and out. He longs for the cleansing that only God can provide. He knows that God is still there and God's holy Spirit remains but he has turned his back on God and the result has been disastrous. David cannot undo what he has committed; there is no turning back the clock. And so he appeals to God...
David's appeal is based on his own frank confession and his knowledge of God's power, mercy and integrity. As Creator, God has the power to re-create us. God's instinct is to forgive and to heal - all injured parties. God always honours his commitments, even though we do not.
We may find it hard to identify with the extreme predicament David faces but, because it is in the Bible - and therefore expressive of God's own mind - we can take our cue from David's strategy, in dealing with our own longing for a pure heart and a steadfast spirit.