Matthew Henry on Deuteronomy 33:1-5

To all his precepts, warnings, and prophecies, Moses added a solemn blessing. He begins with a description of the glorious appearances of God, in giving the law. His law works like fire. If received, it is melting, warming, purifying, and burns up the dross of corruption; if rejected, it hardens, sears, pains, and destroys. The Holy Spirit came down in cloven tongues, as of fire; for the gospel also is a fiery law. The law of God written in the heart, is a certain proof of the love of God shed abroad there: we must reckon His law one of the gifts of his grace.