For the believers takes the place of “for them” in order to clear the possible ambiguity in the Greek statement “when they arrived, they prayed for them (that is, for the believers) that they might receive the Holy Spirit.”

In some languages there is a problem in the phrase receive the Holy Spirit, for it could imply that they were refusing to receive the Holy Spirit and that the prayer of Peter and John was that they might be willing to receive the Holy Spirit. This, of course, in not the meaning of the original text. Therefore, one must sometimes translate as “they prayed for the believers that the Holy Spirit would come to them.” This interpretation is reinforced by verse 16.

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on The Acts of the Apostles. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .