John Gill Commentary Psalms 119:12

"Blessed art thou, O Jehovah: Teach me thy statutes." — Psalms 119:12 (ASV)

Blessed [are] you, O Lord
In himself, in his nature, persons, and perfections; the fountain of all happiness to angels and men, in time and to eternity; to whom all blessing, honour, and glory, are to be given. The psalmist takes this method of praising and ascribing blessing to God, for what he had received from him; particularly for teaching him what he had learned, (Psalms 119:7) ; in hopes of succeeding in his following request:

teach me your statutes ;
the knowledge of the best is imperfect. Good men desire to know more of God, of his mind and will, even of his revealed will; and that they may have grace and strength to act in conformity to it; for it is not the bare theory of things they desire to be taught, but the practice of them; and though ministers, and the ministry of the word, and administration of ordinances, may be and are means of teaching; yet there is none teaches like the Lord, Father, Son, and Spirit. The Targum and Syriac versions render it, "teach me your decrees".