The path on which we must meet with salvation and the Savior, just as it must not be darkened through ignorance of the truth, so it should not be slippery from inconstancy at work. Yet like Balaam, who fell down with his eyes open, so we too see with wide-open eyes because of knowledge while we fall from negligence. Willingly and knowingly we commit sin and freely fall. Nor can we make the excuse that the road is slippery: the fault is rather with the foot we stand on, that is, intention of the mind. For who is not walking in slime while he is in the world, while he is living in this body of clay? Therefore it is not so much the road that is at fault as the foot which is not set firmly enough on the way of God!
But the man who falls, shall he not rise again? A righteous man falls seven times a day and rises each time, for the Lord lifts up those who are bowed down and the Lord guides the righteous. For if I said, “My foot is slipping”, then your mercy, O Lord, helped me up. So when you cannot do otherwise, walk along the road, falling and rising, constantly crying out to him whom you desire to follow and to reach. Keep my steps on your paths so that my feet may not slip. And if there is any wicked way in me, that is, any human frailty, lead me in the everlasting way, since it is through you, the Way and the Truth, that I shall come to you, Life eternal. Glory to you for endless ages. Amen.
From Guerric of Igny, Liturgical Sermons I, the Fourth Sermon for Advent (CF8, pp28-29)