These words are from David's last hymn, composed while on his deathbed. ¹ David acknowledges the imperfection of his reign, his failure to live up to God's expectations, Although my house be not so with God, and yet he recognises God's love for him anyway, God's patience and tolerance of his repeated failings. It is David's utter devotion to God, and his desire to serve even as he fails that is remembered by future chroniclers of his reign. David, with all his failures and transgressions, his reign of turmoil is held in higher esteem than his son Solomon who reigned mostly in peace, and achieved architectural greatness. The difference between them is that David was loyal to God until the end, whereas Solomon turned away, As Solomon grew old, his wives turned his heart after other gods, and his heart was not fully devoted to the Lord his God, as the heart of David his father had been.²

We learn here of God's love for the transgressor. God isn't seeking perfection in us except in one way: perfect, unshakeable love, a constant turning towards. Thomas Merton, the Trappist monk and author wrote in his famous prayer, The Road Ahead,

"...I believe that the desire to please you does in fact please you. And I hope I have that desire in all that I am doing. I hope that I will never do anything apart from that desire." ³

David has that desire, and that then is then essential difference between David and Solomon. David turns towards, Solomon turns away. David is redeemed in the minds of all who follow, his faults forgiven. Solomon is looked upon with suspicion, his faults numbered. No matter how many mistakes we make, if we surrender to love we are always redeemable. We are always loveable until we reject love itself. And perhaps this latter state is what is meant by 'hell on earth'.

¹ The complete hymn can be read here: 2 Samuel 23:1-7
² 1 Kings 11:4-8
³ The full Thomas Merton prayer can be read here. The title used is colloquial.