It is interesting to note, by the time we reach the Gospels (some 400 years later), the three items given above are adhered to with religious fervor, but they had lost all moral significance. While they accused the Lord of violating the Sabbath, they went about seeking to murder Him! In Luke’s Gospel, the Lord tells the pious religious sect of that day: “Woe unto you, Pharisees! For ye tithe mint and rue and all manner of herbs, and pass over judgment and the love of God: these ought ye to have done, and not to leave the other undone” (Luke 11:42). Such is man in the flesh.
It is easy to fall into a habit without having the heart exercised; when these habits are enforced, they will appear as legality. Furthermore, because there is no reality, legality is accompanied by hypocrisy, and, often, outright immorality. In the case of Israel, it was not the things mentioned — separation, honoring the Sabbath and tithing — that were wrong, but the manner in which they were taken up. They became a purely human thing apart from God, and, consequently, though there was much religious pride, they were in no moral state to recognize the Lord Jesus as Christ when He came.
It would have been equally wrong, however, to pass over these things. If the former condition represents the state of the Pharisees, then this latter attitude describes the Sadducees. So it is today; many complain of legality, and perhaps there is that cold, religious formalism. However, to abandon the truths of Scripture is an error in the opposite direction. True submission and obedience to God and His Word is the only right path.