Albert Barnes Commentary Psalms 35:7

"For without cause have they hid for me their net [in] a pit; Without cause have they digged [a pit] for my soul." — Psalms 35:7 (ASV)

For without cause have they hid for me their net in a pit—see Psalms 7:15 and Psalms 9:15. This figure is derived from hunting. The idea is that of digging a pit or hole for a wild beast to fall into, with a net so concealed that the animal could not see it, and that might be suddenly drawn over it to secure it.

The reference here is to plans that are laid to entrap and ruin others: plots that are concocted to secure destruction before one is aware. The psalmist says that, in his case, they had done this without “cause,” or without any sufficient reason. He had done them no wrong; he had given them no semblance of an excuse for their conduct.

Which without cause they have digged for my soul—for my life. That is, they have dug a pit into which I might fall, and into which they designed that I should fall, though I have never done anything to give them occasion to seek my destruction.