Albert Barnes Commentary Mark 12:26

"But as touching the dead, that they are raised; have ye not read in the book of Moses, in [the place concerning] the Bush, how God spake unto him, saying, I [am] the God of Abraham, and the God of Isaac, and the God of Jacob?" — Mark 12:26 (ASV)

How in the bush. This refers to the events at the burning bush. See Exodus 3:6. It signifies that part of the book of Exodus which contains the account of the burning bush. When there were no chapters and verses, it was the easiest way of quoting a book of the Old Testament by its subject, and this method was often used by the Jews. See, for example, Mark 12:28–34. See also Matthew 22:34-40.