21 Say then, Lord our God, what do You enjoin your people, Your Israel? “Immolate to God the sacrifice of praise”. Let us also say to Him, “In me, O God, are your vows, which I will render of prose to You.” I had feared lest You might enjoin something which would be out of my power, which I was counting to be in my pen, and but now perchance it had been taken away by a thief. What do You enjoin me? “Immolate to God the sacrifice of praise.” Let me revert to myself, wherein I may find what I may immolate: let me revert to myself; in myself may I find immolation of praise: be Your altar my conscience. We are without anxiety, we go not into Arabia in quest of frankincense: not any bags of covetous dealer do we sift: God requires of us the sacrifice of praise. Zacchæus had the sacrifice of praise in his patrimony; the widow had it in her bag; some poor host or other has had it in his jar: another neither in patrimony, nor in bag, nor in jar, has had anything, had it wholly in his heart: salvation was to the house of Zacchæus; and more this poor widow cast in than those rich men: this man, that does offer a cup of cold water, shall not lose his reward: but there is even “peace on earth to men of good will.” “Immolate to God the sacrifice of praise.” O sacrifice gratuitous, by grace given! I have not indeed bought this to offer, but You have given: for not even this should I have had. And this is the immolation of the sacrifice of praise, to render thanks to Him from whom you have whatever of good you have, and by whose mercy is forgiven you whatsoever of evil of yours you have. “Immolate to God the sacrifice of praise: and render to the Highest your prayers.” With this odour the Lord is well pleased.
22. “And call thou upon Me in the day of your tribulation: and I will draw you forth, and you shall glorify Me”. For thou oughtest not to rely on your powers, all your aids are deceitful. “Upon Me call thou in the day of tribulation: I will draw you forth, and you shall glorify Me.” For to this end I have allowed the day of tribulation to come to you: because perchance if you were not troubled, you would not call on Me: but when you are troubled, you call on Me; when you call upon Me, I will draw you forth; when I shall draw you forth, you shall glorify Me, that you may no more depart from Me. A certain man had grown dull and cold in fervour of prayer, and said, “Tribulation and grief I found, and on the Name of the Lord I called.” He found tribulation as it were some profitable thing; he had rotted in the slough of his sins; now he had continued without feeling, he found tribulation to be a sort of caustic and cutting. “I found,” he says, “tribulation and grief, and on the Name of the Lord I called.” And truly, brethren, tribulations are known to all men. Behold those afflictions that abound in mankind; one afflicted with loss bewails; another smitten with bereavement mourns; another exiled from country grieves and desires to return, deeming sojourning intolerable; another's vineyard is hailed upon, he observes his labours and all his toil spent in vain. When can a human being not be made sad? An enemy he finds in a friend. What greater misery in mankind? These things all men do deplore and grieve at, and these are tribulations: in all these they call upon the Lord, and they do rightly. Let them call upon God, He is able either to teach how it must be borne, or to heal it when borne. He knows how not to suffer us to be tried above that we are able to bear. Let us call upon God even in those tribulations: but these tribulations do find us; as in another Psalm is written, “Helper in tribulations which have found us too much:” there is a certain tribulation which we ought to find. Let such tribulations find us: there is a certain tribulation which we ought to seek and to find. What is that? The above-named felicity in this world, abundance of temporal things: that is not indeed tribulation, these are the solaces of our tribulation. Of what tribulation? Of our sojourning. For the very fact that we are not yet with God, the very fact that we are living amid trials and difficulties, that we cannot be without fear, is tribulation: for there is not that peace which is promised us. He that shall not have found this tribulation in his sojourning, does not think of going home to his father-land. This is tribulation, brethren. Surely now we do good works, when we deal bread to the hungry, home to the stranger, and the like: tribulation even this is. For we find pitiful objects upon whom we show pity; and the pitiful case of pitiful objects makes us compassionate. How much better now would it be with you in that place, where you find no hungry man whom you may feed, where you find no stranger whom you may take in, no naked man whom you may cover, no sick man whom you may visit, no litigant whom you may set at one! For all things in that place are most high, are true, are holy, are everlasting. Our bread in that place is righteousness, our drink there is wisdom, our garment there is immortality, our house is everlasting in the heavens, our steadfastness is immortality: does sickness come over? Does weariness weigh down to sleep? No death, no litigation: there peace, quiet, joy, righteousness. No enemy has entrance, no friend falls away. What is the quiet there? If we think and observe where we are, and where He that cannot lie has promised that we are to be, from His very promise we find in what tribulation we are. This tribulation none finds, but he that shall have sought it. You are whole, see if you are miserable; for it is easy for him that is sick to find himself miserable: when you are whole, see if you are miserable; that you are not yet with God. “Tribulation and grief I found, and on the Name of the Lord I called.” “Immolate,” therefore, “to God the sacrifice of praise.” Praise Him promising, praise Him calling, praise Him exhorting, praise Him helping: and understand in what tribulation you are placed. Call upon (Him), you shall be drawn forth, you shall glorify, shall abide.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)