Num. xxi. 9; John iii. 14.  The Jerusalem Editor asks, “How did Moses complete the figure by fixing the serpent to a cross?  First he set up the wood and fixed it in the earth as a post:  then by putting the brazen serpent athwart (πλαγίως, he formed a figure of the Cross.”  Cf. Barnab. Epist. c. xii.; Justin M. (Apol. i. c. 60); Iren. (Hæres. IV. c. 2); Tertull. adv. Judæos, c. 10).