Adam Clarke on Matthew 6:32

For after all these things do the Gentiles seek - The fifth reason against solicitude about the future is - that to concern ourselves about these wants with anxiety, as if there was no such thing as a providence in the world; with great affection towards earthly enjoyments, as if we expected no other; and without praying to God or consulting his will, as if we could do any thing without him: this is to imitate the worst kind of heathens, who live without hope, and without God in the world.

Seek - Επιζητει from επι, intensive, and ζητεω, I seek, to seek intensely, earnestly, again and again: the true characteristic of the worldly man; his soul is never satisfied - give! give! is the ceaseless language of his earth-born heart.

Your heavenly Father knoweth, etc. - The sixth reason against this anxiety about the future is - because God, our heavenly Father, is infinite in wisdom, and knows all our wants. It is the property of a wise and tender father to provide necessaries, and not superfluities, for his children. Not to expect the former is an offense to his goodness; to expect the latter is injurious to his wisdom.