What is the meaning of Matthew 23:23-24?

23 Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cummin, and have omitted the weightier matters of the law, judgment, mercy, and faith: these ought ye to have done, and not to leave the other undone. 24 Ye blind guides, which strain at a gnat, and swallow a camel. (Matthew 23:23-24 KJV)

William Burkitt’s Commentary

The next woe denounced is for the Pharisees ostentation of a precise keeping of the law in smaller matters, and neglecting weightier duties: They pay tythe of mint, anise, and cummin; but at the omitted judgment, mercy and faith; that is, just dealing with men, charity towards the poor, and faithfulness in their promises and covenants one with another. This, says our Saviour, is to strain at a gnat and swallow a camel. A proverbial expression, intimating that some persons pretend great niceness and scrupulosity about small matters, and none or but little about duties of the greatest moment.

Hence, Note, 1. That hypocrites lay the greatest stress upon the least matters in religion, and place holiness most in those things where God places it least. Ye tythe mint, &c. but neglect the weightier matters of the law. This is indeed the bane of all religion and true piety, to prefer ritual and human institutions before divine commands, and the practice of natural religion. Thus to do, is a certain sign of gross hypocrisy.

Observe, 2. That although some duties are of greater moment than others, yet a good man will omit none, but perform every duty the least as well as the greatest, in obedience to the command of God. These things ought ye to have done, and not to leave the other undone.