The first word of the discourse proper means "take heed" (Gr. blepete). This word occurs four times in the following verses indicating that warning is an important theme ( Mark 13:9; Mark 13:23; Mark 13:33). Here Jesus warned the disciples about people who would claim to be the Messiah. There would be many of them before He would return. Mark"s "I am" is a divine name (cf. Exodus 3:14; John 8:58). Jesus said these false Messiahs would claim to be God as well as Messiah. [source][source][source]