10 Even once was Christ sacrificed for us, when we believed; then was thought; but now there are the remnants of thought, when we remember Who has come to us, and what He has forgiven us; by means of those very remnants of thought, that is, by means of the memory herself, He is daily so sacrificed for us, as if He were daily renewing us, that has renewed us by His first grace. For now the Lord has renewed us in Baptism, and we have become new men, in hope indeed rejoicing, in order that in tribulation we may be patient: nevertheless, there ought not to escape from our memory that which has been bestowed upon us. And if now your thought is not what it was—for the first thought was to depart from sin: but now thou dost not depart, but at that time departed—be there remnants of thought, lest He who has made whole escape from memory....
11. “Vow ye, and pay to the Lord our God”. Let each man vow what he is able, and pay it. Do not vow and not pay: but let every man vow, and pay what he can. Be not slow to vow: for you will accomplish the vows by powers not your own. You will fail, if on yourselves ye rely: but if on Him to whom you vow ye rely, you will be safe to pay. “Vow ye, and pay to the Lord our God.” What ought we all in common to vow? To believe in Him, to hope from Him for life eternal, to live godly according to a measure common to all. For there is a certain measure common to all men. To commit no theft is not a thing enjoined merely upon one devoted to continence, and not enjoined upon the married woman: to commit no adultery is enjoined upon all men: not to love wine-bibbing, whereby the soul is swallowed up, and does corrupt in herself the Temple of God, is enjoined to all alike: not to be proud, is enjoined to all men alike: not to slay man, not to hate a brother, not to lay a plot to destroy any one, is enjoined to all in common. The whole of this we all ought to vow. There are also vows proper for individuals: one vowes to God conjugal chastity, that he will know no other woman besides his wife: so also the woman, that she will know no other man besides her husband. Other men also vow, even though they have used such a marriage, that beyond this they will have no such thing, that they will neither desire nor admit the like: and these men have vowed a greater vow than the former. Others vow even virginity from the beginning of life, that they will even know no such thing as those who having experienced have relinquished: and these men have vowed the greatest vow. Others vow that their house shall be a place of entertainment for all the Saints that may come: a great vow they vow. Another vowes to relinquish all his goods to be distributed to the poor, and go into a community, into a society of the Saints: a great vow he does vow. “Vow ye, and pay to the Lord our God.” Let each one vow what he shall have willed to vow; let him give heed to this, that he pay what he has vowed. If any man does look back with regard to what he has vowed to God, it is an evil. Some woman or other devoted to continence has willed to marry: what has she willed? The same as any virgin. What has she willed? The same as her own mother. Hath she willed any evil thing? Evil certainly. Why? Because already she had vowed to the Lord her God. For what has the apostle Paul said concerning such? Though he says that young widows may marry if they will: nevertheless he says in a certain passage, “but more blessed she will be, if so she shall have remained, after my judgment.” He shows that she is more blessed, if so she shall have remained; but nevertheless that she is not to be condemned, if she shall have willed to marry. But what says he concerning certain who have vowed and have not paid? “Having,” he says, “judgment, because the first faith they have made void.” What is, “the first faith they have made void”? They have vowed, and have not paid. Let no brother therefore, when placed in a monastery, say, I shall depart from the monastery: for neither are they only that are in a monastery to attain unto the kingdom of Heaven, nor do those that are not there not belong unto God. We answer him, but they have not vowed; you have vowed, you have looked back. When the Lord was threatening them with the day of judgment, He says what? “Remember Lot's wife.” To all men He spoke. For what did Lot's wife? She was delivered from Sodom, and being in the way she looked back. In the place where she looked back, there she remained. For she became a statue of salt, in order that by considering her men might be seasoned, might have sense, might not be infatuated, might not look back, lest by giving a bad example they should themselves remain and season others. For even now we are saying this to certain of our brethren, whom perchance we may have seen as it were weak in the good they have purposed. And will you be such an one as he was? We put before them certain who have looked back. They are savourless in themselves, but they season others, inasmuch as they are mentioned, in order that fearing their example they may not look back. “Vow ye, and pay.” For that wife of Lot to all does belong. A married woman has had the will to commit adultery; from her place whither she had arrived she looked back. A widow who had vowed so to remain has willed to marry, she has willed the thing which was lawful to her who has married, but to herself was not lawful, because from her place she has looked back. There is a virgin devoted to continence, already dedicated to God; let her have also the other gifts which truly do adorn virginity itself, and without which that virginity is unclean. For what if she be uncorrupt in body and corrupt in mind? What is it that he has said? What if no one has touched the body, but if perchance she be drunken, be proud, be contentious, be talkative? All these things God does condemn. If before she had vowed, she had married, she would not have been condemned: she has chosen something better, has overcome that which was lawful for her; she is proud, and does commit so many things unlawful. This I say, it is lawful for her to marry before that she vowes, to be proud is never lawful. O thou virgin of God, you have willed not to marry, which is lawful: thou dost exalt yourself, which is not lawful. Better is a virgin humble, than a married woman humble: but better is a married woman humble, than a virgin proud. But she that looked back upon marriage is condemned, not because she has willed to marry; but because she had already gone before, and has become the wife of Lot by looking back. Be not slow, that are able, whom God does inspire to seize upon higher callings: for we do not say these things in order that you may not vow, but in order that you may vow and may pay. Now because we have treated of these matters, thou perchance wast willing to vow, and now art not willing to vow. But observe what the Psalm has said to you. It has not said, “Vow not;” but, “Vow and pay.” Because you have heard, “pay,” will you not vow? Therefore were you willing to vow, and not to pay? Nay, do both. One thing is done by your profession, another thing will be perfected by the aid of God. Look to Him who does guide you, and you will not look back to the place whence He is leading you forth. He that guides you is walking before you; the place from whence He is guiding you is behind you. Love Him guiding, and He does not condemn you looking back.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)