George Haydock's Catholic Commentary
Psalms 21:15
Water, in the agony, or on the cross, fainting away, Josue vii. 5. --- Bones. In extreme pain, (Calmet) they have been dislocated. (Haydock) --- The bones signify the apostles, who were scattered through the world, to propagate the gospel. (St. Augustine) --- Heart. Which lives and dies first, is now like wax in the fire. (Worthington)