O God, thou hast taught me from my youth - See Psalms 71:5-6. That is, God had guided and instructed him from his earliest years. He had made known to him his own being and perfections; he had made his duty plain; he had led him along the dangerous path of life.
And hitherto have I declared - I have made known. That is, he had done this by public praise; he had done it by his writings; he had done it by maintaining and defending the truth. In all situations of life, up to that time, he had been willing to stand up for God and his cause.
Thy wondrous works - See Psalms 9:1, note; Psalms 26:7, note. Doings or acts which were suited to attract attention; to awe the mind by their greatness; to inspire confidence by their wisdom.