Exegesis:

ērxato legein ‘he began to say.’ Revised Standard Version is probably justified in giving full force to archomai ‘begin’ in this verse, rather than regarding it as virtually meaningless auxiliary (cf. 1.45), as does Translator’s New Testament.

idou hēmeis ‘behold we’: the pronoun ‘we’ is probably emphatic, in contrast with the rich man who was not willing to leave anything (cf. Gould).

For aphiēmi ‘leave’ cf. 2.5, and akoloutheō ‘follow’ cf. 1.18. Gould and Taylor call attention to the use of the aorist aphēkamen ‘we left,’ describing the decisive act of renunciation, and the perfect ēkolouthēkamen ‘we have followed,’ describing the permanent role of discipleship.

Translation:

Lo in some languages is equivalent to ‘look here’ or ‘mind you.’ It is an emphatic element, designated to call special attention to what is said. It does not imply literal ‘looking.’

Left everything may require expansion to ‘left all that we had,’ in order for it to be understood in the sense of renunciation rather than merely of getting up and departing, or of inadvertently leaving things behind.

For follow see 1.17.

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 .