Blessed are they who do hunger and thirst after righteousness: for they shall be filled.
All Commentaries on Matthew 5:6 Go To Matthew 5
Theophylact of Ochrid
Since He is about to speak about almsgiving, He first shows that one must pursue righteousness, and not give alms from what has been acquired by theft and extortion. And one must avidly practice righteousness, for this is what it means to "hunger and thirst’’. Since it is the greedy who are thought to be well off and satisfied, Jesus says that it is rather the righteous who shall be filled, even here in this life, for what is theirs they possess with surety.