George Haydock's Catholic Commentary
Psalms 87:9
Delivered up, to prison. (Berthier) --- The disciples abandoned our Saviour; St. Peter, with a curse, denied that he ever knew him, (Mark xiv. 71.; Haydock) and Judas betrayed him. It is not so easy to explain this of the captives in general, though it might refer to the psalmist. (Calmet) --- At Babylon, the Israelites were not imprisoned, but left to multiply, Jeremias xxix. 5. (Berthier)