Exegesis:
grēgoreite kai proseuchesthe hina ‘you (plural) must watch and pray that’: Revised Standard Version takes ‘that’ to refer to the content of the prayer (as in v. 35 and 13.38); if, however, both verbs be taken with hina, it could indicate purpose – ‘watch and pray, in order that…’ (so Translator’s New Testament; cf. Moffatt “so that”).
peirasmon (only here in Mark; cf. peirazō 1.13) ‘temptation’: the context seems to demand the meaning of ‘temptation’ leading to sin, and not merely the idea of ‘trial’ or ‘testing.’
pneuma (cf. 2.8) … sarx (cf. 10.8) ‘spirit … flesh’: here presented as distinct and antithetical elements of man’s nature. The contrast between the two, say Arndt & Gingrich, is between the will as opposed to inferior feelings such as fear, anxiety, etc. which are attributed to the ‘flesh.’
prothumon (only here in Mark) ‘ready,’ ‘willing,’ ‘eager.’
asthenēs (only here in Mark); cf. astheneō (6.56) ‘weak,’ ‘powerless.’
Translation:
Watch would seem to be best translated as ‘stay awake’ or ‘stay alert.’
Enter into temptation is an awkward idiom in most languages, for one does not literally ‘enter into’ such an experience. In Tzeltal this concept is expressed as ‘end by being tempted,’ and in Copainalá Zoque one must say ‘fall when Satan tries you.’ In Highland Puebla Nahuatl one may ‘enter into sin,’ but not ‘enter into temptation.’
The spirit … the flesh is a fundamental contrast, but one which is variously expressed in different languages. Often, however, spirit is equivalent to ‘heart’ (Eastern Highland Otomi, Loma (Liberia), Guerrero Amuzgo, Highland Puebla Nahuatl ), and flesh may be rendered as ‘body’ (Guerrero Amuzgo, Highland Puebla Nahuatl , Tzeltal), ‘you yourself’ (Central Tarahumara). The following translations are illustrative of the contrastive expressions: ‘your hearts are ready but your bodies are weak’ (Highland Puebla Nahuatl ), ‘your heart is strong but you yourselves are not strong’ (Central Tarahumara), ‘your heart has strength, but your body does not have strength’ (Tzeltal), ‘your heart desires to do good, but your heart is weak,’ in which ‘heart’ must be used in both clauses since it not only stands for the center of the personality, but is also the symbol of typical human nature (Loma (Liberia)).
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 .