George Haydock's Catholic Commentary
Psalms 15:9
Tongue. Hebrew, "glory." Yet Protestants translate, "tongue," (Acts ii.) as St. Peter follows the Septuagint (Haydock) and he surely understood the force of the Hebrew; so that his testimony in their favour is very strong. Commentators observe that the tongue manifests the joy of the heart, (Berthier) and the same word is used for the soul, Psalm vii. 6. (Calmet) --- Yet very different words signify the tongue and glory; and we follow the text, adopted by the apostle. Joy naturally flows from the presence of the best of friends. (Berthier) --- Our Saviour sometimes suspended this joy, that he might suffer the more for us. (Calmet)