“Blessed are they which do hunger and thirst after righteousness: for they shall be filled” (Mt 5:6).
“As soon as I have wept for my sins, I begin to hunger and thirst after righteousness. He who is afflicted with any sore disease, hath no hunger.” -St. Ambrose
“It is not enough that we desire righteousness, unless we also suffer hunger for it, by which expression we may understand that we are never righteous enough, but always hunger after works of righteousness.” -St. Jerome
“He hungers after righteousness who desires to walk according to the righteousness of God; he thirsts after righteousness who desires to get the knowledge thereof.” -Pseudo-Chrysostom
“As He was going on to speak of mercy, He shows beforehand of what kind our mercy should be, that it should not be of the gains of plunder or covetousness; hence He ascribes to righteousness that which is peculiar to avarice, namely, to hunger and thirst.” -St. John Chrysostom
“The blessedness which He appropriates to those who hunger and thirst after righteousness shows that the deep longing of the saints for the doctrine of God shall receive perfect replenishment in heaven; then they shall be filled.” -St. Hilary of Poitiers
“Such is the bounty of a rewarding God, that His gifts are greater than the desires of the saints.” -Pseudo-Chrysostom
“He speaks of food with which they shall be filled at this present; to wit, that food of which the Lord spake, ‘My food is to do the will of my Father,’ that is, righteousness, and that water of which whoever drinks it shall be in him ‘a well of water springing up to life eternal.'” -St. Augustine
“This is again a promise of a temporal reward; for as covetousness is thought to make many rich, He affirms on the contrary that righteousness rather makes rich, for he who loves righteousness possesses all things in safety.” -St. John Chrysostom
Quotations from St. Thomas Aquinas, Catena Aurea: Commentary on the Four Gospels Collected Out of the Works of the Fathers, Vol. I, Part I (Oxford: John Henry Parker, 1841).