20 Nor let any one marvel, beloved brethren, that even some of the confessors advance to these lengths, and thence also that some others sin thus wickedly, thus grievously. For neither does confession make a man free from the snares of the devil, nor does it defend a man who is still placed in the world, with a perpetual security from temptations, and dangers, and onsets, and attacks of the world; otherwise we should never see in confessors those subsequent frauds, and fornications, and adulteries, which now with groans and sorrow we witness in some. Whosoever that confessor is, he is not greater, or better, or dearer to God than Solomon, who, although so long as he walked in God's ways, retained that grace which he had received from the Lord, yet after he forsook the Lord's way he lost also then Lord's grace. And therefore it is written, “Hold fast that which you have, lest another take your crown.” But assuredly the Lord would not threaten that the crown of righteousness might be taken away, were it not that, when righteousness departs, the crown must also depart.
Source: The Treatises of Cyprian (New Advent)