But do not thou yield unto them: for there lie in wait for him of them more than forty men, which have bound themselves with an oath, that they will neither eat nor drink till they have killed him: and now are they ready, looking for a promise from thee.
Note 3 at Ac 23:21: This amounted to a suicide pact. Since Paul was a prisoner, there would be some type of Roman guard accompanying him. For these men to kill Paul, they would have to fight the Roman soldiers. This would have certainly brought a swift death for them, even if they had been successful in their mission to kill Paul.