The parallel account in Matt 5:6 is possibly more helpful:
Blessed are those who hunger and thirst for righteousness, for they
will be filled.
In commenting on this, Ellicott says:
(6) Which do hunger and thirst.—We seem in this to hear the lesson
which our Lord had learnt from the recent experience of the
wilderness. The craving of bodily hunger has become a parable of that
higher yearning after righteousness, that thirsting after God, even as
the hart desireth the water-brooks, which is certain, in the end, to
gain its full fruition. Desires after earthly goods are frustrated, or
end in satiety and weariness. To this only belongs the promise that
they who thus “hunger and thirst” shall assuredly be filled. The same
thoughts meet us again in the Gospel which in many respects is so
unlike that of St. Matthew. (Comp. John 4:14; John 4:32).
Barnes makes similar remarks:
Blessed are they which do hunger ... - Hunger and thirst, here, are
expressive of strong desire. Nothing would better express the strong
desire which we ought to feel to obtain righteousness than hunger and
thirst. No needs are so keen, none so imperiously demand supply, as
these. They occur daily, and when long continued, as in case of those
shipwrecked, and doomed to wander months or years over burning sands,
with scarcely any drink or food, nothing is more distressing. An
ardent desire for anything is often represented in the Scriptures by
hunger and thirst, Psalm 42:1-2; Psalm 63:1-2. A desire for the
blessings of pardon and peace; a deep sense of sin, and want, and
wretchedness, is also represented by thirsting, Isaiah 55:1-2.
