9 The next condition is, that the man who has not walked in the counsel of the ungodly shall not stand in the way of sinners. For there are many whose confession concerning God, while it acquits them of ungodliness, yet does not set them free from sin; those, for example, who abide in the Church but do not observe her laws; such are the greedy, the drunken, the brawlers, the wanton, the proud, hypocrites, liars, plunderers. No doubt we are urged towards these sins by the promptings of our natural instincts; but it is good for us to withdraw from the path into which we are being hurried and not to stand therein, seeing that we are offered so easy a way of escape. It is for this reason that the man who has not stood in the way of sinners is happy, for while nature carries him into that way, religious belief draws him back.
Source: Homilies on the Psalms (New Advent)