Commentaries:
Isaiah 42:21 contains an important principle for understanding Christ's ministry: "The LORD is well pleased for His righteousness' sake; He will magnify the law and make it honorable." Magnify means "to enlarge." We often focus on Jesus magnifying the law in the Sermon on the Mount, where He taught that anger and hate are the spirit of murder, and lust, the spirit of adultery. However, throughout His ministry Jesus deliberately and frequently focused attention on the Sabbath to magnify its intent.
John W. Ritenbaugh
The Fourth Commandment (Part Two): Christ's Attitude Toward the Sabbath
This is a most important scripture for understanding Christ's ministry. A major part of the purpose of His ministry is to magnify the law. The Sermon on the Mount is the focal point of His doing this. In the Sermon on the Mount, we learn that anger and hate are the spirit of murder, magnifying the sixth commandment. We also learn there that lust is the spirit of adultery, magnifying, clarifying, and explaining in sharper detail so that we can understand and see its application.
Jesus deliberately and frequently focused His attention on the Sabbath, but not, however, in the Sermon on the Mount. It is too big a subject to be contained there. We find passage after passage where He magnifies the keeping of the Sabbath and thus teaches the intent of the Sabbath.
John W. Ritenbaugh
The Fourth Commandment (Part 2)