I have not departed from thy judgments - Thy law; thy commands. This cannot mean that he had never done this, but that as a great rule of life he had not done it. The character and aim of his life had been obedience, not disobedience. A man may honestly say this, though he may be conscious of much imperfection, and may feel that he has not perfectly carried out such an aim and purpose. No one can be a truly pious man, or have evidence of personal religion, who cannot say in sincerity that he has "not departed in this sense, "from the judgments" (the commands) of God; who cannot look back on his life and say that his course - his aim - his character - since he became a professor of religion - has been, one of obedience to God. Compare 1-John 3:7-9.
For thou hast taught me - Not to himself was this to be traced, but to God; not to any wisdom of his own, but to that which was given him from on high.

I have not departed from thy judgments: for (c) thou hast taught me.
(c) So then of ourselves we can do nothing, but when God inwardly instructs us with his spirit, we feel his graces sweeter than honey.

I have not departed from thy judgments,.... From the precepts of the word, from the ways and worship and ordinances of God; he had not wickedly and on purpose departed from them; whenever he did, it was through inadvertency, the weakness of the flesh, and strength of temptation; nor from the doctrines of the word, which he held fast, knowing of whom he had learned them, as follows:
for thou hast taught me; the nature, excellency, and use of these judgments; he had taught him, by his Spirit, experimentally to understand the doctrines of the word, and practically to observe the precepts of it; and this preserved him from an apostasy from either of them.

Taught me - By thy blessed spirit, illuminating my mind, and working upon my heart.