Psalms 40:9 - Matthew Poole's English Annotations on the Holy Bible

Righteousness, to wit, thy righteousness, as it is expressed in the next verse, i.e. thy faithfulness, as it is there explained; or righteousness properly so called; for both were fully declared and demonstrated in Christ, the former in sending him into the world according to his promise, Acts 13:23, and the latter in inflicting death upon him for man's sin, Romans 3:25,26. In the great congregation; in the most public and solemn assemblies; not only to the Jews, but also to all other nations; to whom Christ preached by his apostles, as is observed, Ephesians 2:17. I have not refrained my lips, to wit, from preaching it, out of sloth, or fear, or self love, but have preached it publicly, and even to the face of mine enemies, though I knew my preaching would cost me my life. Thou knowest; I call thee to witness the truth of what I say.