10 Let not the virgin say, “I shall alone be there.” For Mary shall not be there alone but the widow Anna shall be there also. Let not the woman which has an husband say, “The widow will be there, not I;” for it is not that Anna will be there, and Susanna not be there. But by all means let them who would be there prove themselves hereby, that they who have here a lower place envy not, but love in others the better place. For, for instance, my Brethren, that you may understand me; one man has chosen a married life, another a life of continence; if he who has chosen the married life, has adulterous lusts, he has “looked back;” he has lusted after that which is unlawful.
He too who would wish afterwards to return from continence to a married life, has “looked back;” he has chosen what is in itself lawful, yet he has “looked back.” Is marriage then to be condemned? No. Marriage is not to be condemned; but see whither he had come who has chosen it. He had already got before it. When he was living as a young man in voluptuousness, marriage was before him; he was making his way towards it; but when he had chosen continence, marriage was behind him.
“Remember,” says the Lord, “Lot's wife.” Lot's wife, by looking behind, remained motionless. To whatever point then any one has been able to reach, let him fear to “look back” from thence; and let him walk in the way, let him “follow Christ.” “Forgetting those things which are behind, and stretching forth unto those things which are before, let him by an earnest inward intention press on toward the prize of the calling of God in Christ Jesus.” Let those that are married regard the unmarried as above themselves; let them acknowledge that they are better; let them in them love what themselves have not; and let them in them love Christ.
Source: Sermons on Selected Lessons of the New Testament (New Advent)