A.T. Robertson Commentary Mark 16:20

"And they went forth, and preached everywhere, the Lord working with them, and confirming the word by the signs that followed. Amen." — Mark 16:20 (ASV)

The Lord working with them (του κυριου συνεργουντος). Genitive absolute. This participle not in Gospels elsewhere nor is βεβαιουντος nor the compound επακολουθουντων, all in Paul's Epistles. Πανταχου once in Luke. Westcott and Hort give the alternative ending found in L: "And they announced briefly to Peter and those around him all the things enjoined. And after these things Jesus himself also sent forth through them from the east even unto the west the holy and incorruptible proclamation of the eternal salvation."