Isaiah 58:1-9a
1Cry out! Cease not! Exalt your voice like a trumpet, and announce to my people their wicked acts, and to the house of Jacob their sins.
Psalm 50
3Be merciful to me, O God, according to your great mercy. And, according to the plentitude of your compassion, wipe out my iniquity. 4Wash me once again from my iniquity, and cleanse me from my sin. 5For I know my iniquity, and my sin is ever before me. 6Against you only have I sinned, and I have done evil before your eyes. And so, you are justified in your words, and you will prevail when you give judgment. 7For behold, I was conceived in iniquities, and in sinfulness did my mother conceive me. 8For behold, you have loved truth. The obscure and hidden things of your wisdom, you have manifested to me. 9You will sprinkle me with hyssop, and I will be cleansed. You will wash me, and I will be made whiter than snow. 10In my hearing, you will grant gladness and rejoicing. And the bones that have been humbled will exult. 11Turn your face away from my sins, and erase all my iniquities. 12Create a clean heart in me, O God. And renew an upright spirit within my inmost being. 13Do not cast me away from your face; and do not take your Holy Spirit from me. 14Restore to me the joy of your salvation, and confirm me with an unsurpassed spirit. 15I will teach the unjust your ways, and the impious will be converted to you. 16Free me from blood, O God, the God of my salvation, and my tongue will extol your justice. 17O Lord, you will open my lips, and my mouth will announce your praise. 18For if you had desired sacrifice, I would certainly have given it, but with holocausts, you will not be delighted. 19A crushed spirit is a sacrifice to God. A contrite and humbled heart, O God, you will not spurn.
Matthew 9:14-15
14Then the disciples of John drew near to him, saying, “Why do we and the Pharisees fast frequently, but your disciples do not fast?” 15And Jesus said to them: “How can the sons of the groom mourn, while the groom is still with them? But the days will arrive when the groom will be taken away from them. And then they shall fast.