John Gill Commentary Jeremiah 5:16

"Their quiver is an open sepulchre, they are all mighty men." — Jeremiah 5:16 (ASV)

Their quiver is an open sepulchre The Chaldeans used bows and arrows in fighting; and the quiver is a case for arrows; and the phrase denotes, that their arrows would do great execution, and be very mortal; so that a quiver of them would be as devouring as an open grave, into which many dead are cast. The Septuagint and Arabic versions have not this clause; and the Syriac version renders it, "whose throats are as open sepulchres"; see (Romans 3:13):

they are all mighty men strong in body, of bold and courageous spirits, expert in war, and ever victorious; so that there was no hope of being delivered out of their hands.