Exegesis:

didaskōn ‘teaching’: the participle is probably temporal, ‘while he was teaching.’ It is to be noticed that the text does not say that Jesus was addressing the scribes: it is to be inferred that he was speaking to a group of people (whether there were scribes present or not is of no moment).

hoi grammateis (cf. 1.22) ‘the scribes,’ ‘the teachers of the Law.’

ho christos (cf. 8.29) ‘the Christ’: a title, ‘The Anointed One,’ and not a proper name.

huios Dauid (cf. 10.47) ‘son of David,’ ‘descendant of David,’ ‘David’s offspring.’ As a Messianic title, ‘son of David’ indicated that the Messiah would be of the lineage of David.

Inasmuch as a faulty interpretation may influence the translation of this incident, it is well to notice that Jesus, in raising the question and quoting Ps. 110.1, is not denying the fact that the Messiah, indeed, would be a descendant of David (as attested in many passages in the O.T.). Implicit in the title ‘son of David,’ however, was the concept that the Messiah would be somewhat less than David, or, at the most, one like unto David: so Jesus says, in effect, “not only David’s son, but David’s Lord” (Rawlinson). The purpose of the argument, as Taylor points out, “is not to deny the Davidic descent of the Messiah, but to suggest that a much higher view of his origin is necessary since David calls him ‘lord.’”

Translation:

For taught see 2.13, and for temple see 11.11.

A rendering of taught may require an object, since in many languages it is a transitive verb, e.g. ‘taught the people.’

For scribes see 1.22.

Son must in some instances be rendered ‘descendant’ or ‘offspring.’ In certain languages one must use ‘grandson’ so as to avoid the interpretation that the Christ was to be regarded as the immediate biological son of David.

The basic problem with this verse, however, as suggested above, is that the form would seem to deny the fact that Jesus was the offspring of David. To avoid this implication, which may be much stronger in some languages than in Greek or English, one may be obliged to insert ‘merely’ or ‘just,’ e.g. ‘the Christ is just the son of David,’ implying inferiority of status.

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 .