David does not merely long for certain spiritual excellences; he goes to God for them. And his reasons for doing so are plain. If you will look at the former verses of this psalm, you will see that he had found out two things about his sin, both of which make him sure that he can only be what he should be by God's help. He had learned what his crimes were in relation to God, and he had further learned what they indicated about himself. The teaching of his bitter experience as to the former of these two matters lies in that saying which some people have thought strange. 'Against _Thee only_ have I sinned.' What! Had he not committed a crime against human law? had he not harmed Uriah and Bathsheba? were not his deeds an offence to his whole kingdom? Yes, he knew all that; but he felt that over and above all that was black in his deed, considered in its bearing upon men, it was still blacker when it was referred to God; and a sadder word than 'crime' or 'fault' had to be used about it. I have done wrong as against my fellows, but worse than that, I have _sinned_ against God. The notion of _sin_ implies the notion of God. Sin is wilful transgression of the law of _God_. An atheist can have no conception of sin. But bring God into human affairs, and men's faults immediately assume the darker tint, and become men's sins. Therefore the need of prayer if these evils are to be blotted out. If I had done crime against man only, I should not need to ask God for pardon or cleansing; but I have sinned against Him, and done this evil in His sight, therefore my desires for deliverance address themselves to Him, and my longings for purity must needs break into the cry of entreaty to that God with whom are forgiveness and redemption from all iniquity. And still further, looking at the one deed, he sees in it something more than an isolated act. It leads him down to its motive; that motive carries him to the state of mind in which it could have power; that state of mind, in which the motive could have power, carries him still deeper to the bias of his nature as he had received it from his parents. And thinking of how he had fallen, how upon his terraced palace roof there the eye had inflamed the heart, and the heart had yielded so quickly to the temptations of the eye, he finds no profounder explanation of the disastrous eclipse of goodness than this: 'Behold! I was shapen in iniquity.'