Exegesis:

nekrōn … zōntōn ‘of dead people … of living people.’

zaō (cf. 5.23) ‘to live’: in Mark only here is the participle used.

polu planasthe ‘you are very much mistaken.’ For polu as an adverb ‘much,’ ‘very’ cf. 10.48; for the verb cf. v. 24.

Translation:

This verse is mistranslated and misinterpreted about as much as any other verse in the New Testament, since a literal rendering is frequently understood to mean that God has no relationship to the dead. Such literal translations need to be abandoned in many instances, with a resultant complete recasting of the sentence, e.g. ‘These dead persons, for whom God is their God, are really living’; ‘He is the God of living people, including those who are regarded as dead, but they are living’; or ‘If God is the God of certain people, that means that they must have life, even though they have died.’ These alternatives are admittedly extreme “paraphrases,” in the general sense of this term, but the only alternative in many languages is to state categorically that God has nothing to do with people after they are dead and that his only concern is for the living – an obvious untruth, but one which has been emphatically stated in numerous literal translations.

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 .