Exegesis:

tē prōtē hēmera ‘on the first day’: in the strictest sense the Passover lambs were not slain ‘on the first day of the Unleavened Bread,’ which was 15th Nisan (cf. v. 1), but on the day preceding, i.e. the afternoon of the 14th Nisan. It has been suggested by commentators, therefore, that the phrase be taken to mean ‘on the day before the Unleavened Bread.’ It would appear probable, however, that here the word ‘day’ is used in a general sense, and not in the precise meaning of the twenty-four hour period running from sundown to sundown. On Thursday afternoon, 14th Nisan, the lambs were slain, and at sundown that evening began the first day of the Unleavened Bread, 15th Nisan. In Lk. 22.7 a similar indication of time is found.

hote to pascha ethuon ‘when they slew the Passover (lamb)’: the verb is used in an impersonal sense, meaning ‘when the Passover lamb was slain.’ The imperfect ethuon ‘they were slaying’ indicates here a customary action: ‘when it was customary for them to kill.’

to pascha (cf. v. 1) ‘the Passover lamb’: here the animal is referred to, not the Feast, as in v. 1. The singular ‘passover lamb’ is used generically for all the lambs slain that afternoon.

thuō (only here in Mark) ‘slaughter,’ ‘kill,’ ‘sacrifice.’ The Greek word in the Septuagint translates both shachat ‘slay’ and zavach ‘sacrifice,’ and may mean either one in this passage.

pou theleis apelthontes hetoimasōmen…; ‘where do you want us to go and prepare…?’

hetoimazō (cf. 1.3) ‘prepare,’ ‘make ready.’

hina phagēs ‘in order that you may eat,’ ‘for you to eat.’

to pascha here is ‘the Passover meal’ (as in v. 14), in contrast with the Passover feast in v. 1, and Passover lamb in the first part of this verse.

Translation:

Day of Unleavened Bread often requires some type of more precise definition of the relationship between ‘day’ and ‘unleavened bread,’ e.g. ‘day of the festival of unleavened bread’ or ‘day of the time when unleavened bread was eaten.’ Certainly one must not use a typical possessive construction, ‘unleavened bread’s day,’ as has been done in so many languages.

Sacrificed in this context must often be translated merely as ‘killed.’

Passover lamb has not infrequently been translated as ‘the passing-over lamb,’ a phrase which was interpreted to mean that the lamb in question passed over something. In order that the relationships between the component parts may be clear one may render this phrase as ‘lamb to remember the passing over’ (Amganad Ifugao), ‘lamb of the passing-over day’ (Eastern Krahn), or ‘lamb for the pascua day,’ in which pascua has been borrowed from Spanish (Copainalá Zoque).

Eat the passover may be completely meaningless in a literal translation, e.g. ‘eat the passing-over.’ Hence, one may need to employ a phrase such as ‘eat the meal that reminds people of the passing over.’

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 .