Exegesis:

echete is the imperative (not the indicative) ‘you must have.’

pistin theou ‘faith in God’ in which the genitive theou ‘of God’ indicates the object of faith, not its subject.

Translation:

For faith see 1.15.

The imperative form of Jesus’ statement does provide certain difficulties for the translator, especially in languages in which there are no corresponding forms of this verb. In such instances one may render the passage as ‘you should believe in God,’ ‘you must trust in God,’ or ‘it is necessary that you have confidence in God.’

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 .