John Calvin on Matthew 6:33-34

Matthew 6:33. But rather seek first the kingdom of God This is another argument for restraining excessive anxiety about food. It argues a gross and indolent neglect of the soul, and of the heavenly life. Christ reminds us that there is the greatest inconsistency in men, who are born to a better life, being wholly employed about earthly objects. He who assigns the first rank to the kingdom of God, will not carry beyond moderation his anxiety about food. Nothing is better adapted to restrain the wantonness of the flesh from breaking out in the course of the present life, than meditation on the life of the heavens. The word righteousness may be either understood as applying to God, or to the kingdom: On the latter supposition, we would naturally have expected that, instead of τὴν δικαιοσύνην αὐτοῦ, we would have had τὴν δικαιοσύνην αὐτὢς, when αὐτὢς would have stood for τὢς βασιλείας. — Ed. for we know that the kingdom of God consists in righteousness, (Romans 14:17,) that is, in the newness of spiritual life. All other things shall be added This means, that those things which relate to the present life are but favorable appendages, and ought to be reckoned greatly inferior to the kingdom of God