Exegesis:

epi tō onomati mou (cf. 9.37) ‘in my name’: some difficulty arises from the fact that the phrase ordinarily means ‘on my account,’ ‘for my sake,’ ‘in my behalf’; here, however, it seems to demand the meaning, ‘representing to be me,’ ‘as though they were I,’ since they will say, “I am he.” Arndt & Gingrich suggest ‘using my name’; ‘in my name’ is the reading of most English translations (cf. Vulgate in nomine meo); Lagrange has sous mon nom. Notwithstanding the difficulty, some such translation as Revised Standard Version ‘in my name,’ or ‘under my name,’ will probably convey the meaning without involving the statement in any contradiction.

hoti ‘that’ introduces direct statement.

egō eimi literally ‘I am’ or ‘It is I’ (cf. 6.50); here, clearly, a claim to be the Messiah – ‘I am He’ (cf. 14.62), or, in accordance with Marcan language, ‘I am the Son of man’ (cf. v. 26).

Translation:

For the use of in my name see 9.37, but in this context a special rendering is often required, e.g. ‘making use of my name,’ ‘calling themselves by my name,’ or ‘applying my name to themselves.’

I am he is sometimes very ambiguous, especially as this expression is spoken by Jesus. Hence, ‘I am the Christ’ or ‘I am the Son of man’ is a much closer equivalent. In languages which generally prefer an indirect form of discourse, this statement may be less ambiguous, e.g. ‘they will say that they are I,’ or ‘they will say that they are what I am.’

A further complication may be found in the shift from plural to singular in the form of the direct discourse, e.g. ‘many will come…, each will say, I am he.’ Moreover, the plural of ‘many’ must be interpreted as distributive, not as collective, for each person claims for himself the Messiahship.

For lead many astray see the previous verse.

Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on the Gospel of Mark. (UBS Handbook Series). New York: UBS, 1961. For this and other handbooks for translators see here .