Exegesis:

eiselthousai eis to mnēmeion (cf. 5.2) ‘going into the tomb’: cf. 15.46, and see Lagrange for a description of the tomb as it probably was.

eidon neaniskon kathēmenon en tois dexiois peribeblēmenon stolēn leukēn ‘they saw a young man sitting on the right, wearing a white robe’: the description and the circumstances would imply that the ‘young man’ was, in fact, an angel, and Lagrange refers to 2 Macc. 3.26, 33 for a similar description. A translation should have, however, ‘young man,’ and not ‘angel.’ For neaniskos ‘young man’ cf. 14.51; kathēmai ‘sit’ cf. 2.6; en tois dexiois ‘on the right (side)’ cf. 10.27 (elsewhere in Mark always ek dexiōn); periballō ‘to clothe,’ ‘wear’ (cf. 14.51); stolē ‘robe’ cf. 12.38; leukē ‘white’ cf. 9.3.

exethambēthēsan (cf. 9.15) ‘they were astonished’; perhaps ‘they were alarmed.’ It should be noticed that this compound verb, indicating strong emotion, is used only by Mark in the New Testament.

Translation:

Entering the tomb may be treated as a dependent clause of time, e.g. ‘when they had entered the tomb, they saw…’ or as a coordinate event in prior sequence, e.g. ‘they entered the tomb and saw….’

Saw a young man sitting is a type of construction which requires two clauses in many languages, e.g. ‘saw a young man; he was sitting.’

On the right side must be related to the orientation of the tomb or to the position of the women, not to the right side of Jesus, as some translations have implied, thus giving the impression that Jesus was still in the tomb, though unseen.

Dressed in a white robe would imply a garment which was both long and white, e.g. ‘wearing clothing, long and white’ (Copainalá Zoque).

For amazed see 1.22, 27.

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 .