Re: Please translate into Greek.
This sentence means either ΕΧΕΤΕ ΤΗΝ ΠΙΣΤΗ ΤΟΥ ΘΕΟΥ or ΕΧΕΤΕ ΤΗΝ ΕΜΠΙΣΤΟΣΥΝΗ ΤΟΥ ΘΕΟΥ. Now, in the first case, the sentence means "have the faith of God", that is "God, may believe in you". In the second one the meaning is that "God may trust you", since the word faith means trust, too. In both cases, the preposition "of" implies that the subject of the verb (if we regard the noun "faith" as a verb) is God, and the object is the word "you".
For such sentences, the common preposition is "in". Which in Greek means: ΕΧΕΤΕ ΠΙΣΤΗ ΣΤΟ ΘΕΟ (=believe in God). I hope that I helped.