“This moan, “O wretched man that I am,” expresses the normal experience of the Christian, and any Christian who does not so moan is in an abnormal and unhealthy state spiritually. The man who does not utter this cry daily is either so out of communion with Christ, or so ignorant of the teaching of Scripture, or so deceived about his actual condition, that he knows not the corruptions of his own heart and the abject failure of his own life.
If he is given to behold how far short he falls of attaining to God’s standard; if he discovers how little he resembles the Christ of God; then will he find this language most suited to express his godly sorrow. If God reveals to him the coldness of his love, the pride of his heart, the wanderings of his mind, the evil that defiles his godliest acts, he will cry, “O wretched man that I am.” If he is conscious of his ingratitude, of how little he appreciates God’s daily mercies; if he marks the absence of that deep and genuine fervor which ought ever to characterize his praise and worship; if he recognizes that sinful spirit of rebellion, which so often causes him to murmur or at least chafe against the dispensations of God in his daily life; he will indeed cry. “O wretched man that I am.”
Communion with Christ produces both rejoicing and mourning. It did with Paul. In Romans 7:22 he says, “I delight in the law of God.” Yet only two verses later he cries, “O wretched man that I am!”
Sorrow and groaning, then are not absent from the highest spirituality.”
Arthur Pink “The Christian in Romans 7