20 Explain to us, then, says one, how those that build wood, hay, stubble, on the foundation, do not perish, but “are saved, yet so as by fire”? An obscure question indeed that, but as I am able I tell you briefly. Brethren, there are men altogether despisers of this world, to whom nothing is pleasant that flows in the course of time, they cling not by love to any earthly works, holy, chaste, continent, just, perchance even selling all their goods and distributing to the poor, or “possessing as though they possessed not, and using this world as though not using it.” But there are others who cling to things allowed to infirmity with a degree of affection. He robs not another of his estate, but so loves his own, that if he loses it he will be disturbed. He does not covet another's wife, but so clings to his own, so cohabits with his own, as not therein to keep the measure prescribed in the laws, for the sake of begetting children. He does not take away other men's things, but reclaims his own, and has a law-suit with his brother. For to such it is said, “Now indeed there is altogether a fault among you, because you have law-suits with each other.” But these very suits he orders to be tried in the Church, not to be dragged into court, yet he says they are faults. For a Christian contends for earthly things more than becomes one to whom the kingdom of Heaven is promised. Not the whole of his heart does he raise upward, but some part of it he drags on the earth....Therefore if you love your possession, yet dost not for its sake commit violence, dost not for its sake bear false witness, dost not for its sake commit manslaughter, dost not for its sake swear falsely, dost not for its sake deny Christ: in that you will not for its sake do these things, you have Christ for a foundation. But yet because you love it, and art saddened if you lose it, upon the foundation you have placed, not gold, or silver, or precious stones, but wood, hay, stubble. Saved therefore you will be, when that begins to burn which you have built, yet so as by fire. For let no one on this foundation building adulteries, blasphemies, sacrileges, idolatries, perjuries, think he shall be “saved through fire,” as though they were the “wood, hay, stubble:” but he that builds the love of earthly things on the foundation of the kingdom of Heaven, that is upon Christ, his love of temporal things shall be burned, and himself shall be saved through the right foundation.
21....“And He fed them of the fat of wheat, and from the rock with honey He satisfied them”. In the wilderness from the rock He brought forth water, not honey. “Honey” is wisdom, holding the first place for sweetness among the viands of the heart. How many enemies of the Lord, then, that lie unto the Lord, are fed not only of the fat of wheat, but also from the rock with honey, from the wisdom of Christ? How many are delighted with His word, and with the knowledge of His sacraments, with the unfolding of His parables, how many are delighted, how many applaud with clamour! And this honey is not from any chance person, but “from the rock.” But “the Rock was Christ.” How many, then, are satisfied with that honey, cry out, and say, It is sweet; say, Nothing better, nothing sweeter could be thought or said! And yet the enemies of the Lord have lied unto Him. I like not to dwell any more on matters of grief; although the Psalm ends in terror to this purpose, yet from the end of it, I pray you, let us return to the heading: “Exult unto God our Helper.” Turned unto God.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)