In thinking about this statement at the end of Acts 6:2, we must realize that the apostles have a very unique calling regarding the word of God, as laid out in John 14-16, so if they get sidetracked from their responsibilities, even by a good thing like tangibly caring for the poor, then Christianity gets derailed. How’s that? Even though it was promised in certain situations, like we have seen in Acts 4&5, that the apostles would be given the words to speak in the moment from the Spirit in situations of hostility, typically the apostles needed to spend countless hours studying and preparing to preach and teach in the many gatherings throughout the week. Furthermore, it was through this time of preparation and proclamation of the truth that the Holy Spirit-inspired NT Scriptures would come into being. Thus, consider the implications for the future church once the apostles are dead and gone if they abandon their foundational role at this point. If the primacy of the word of God is neglected or even minimized, then Christians of that time and future times would suffer for it. When you think about it that way, ch.6 poses just as much or more of a legitimate threat to the growth of the church as ch.5.
So the emphasis in their statement in v.2 is on the word “us.” It is not right for US to neglect the word of God to serve tables. We know that they still viewed this kind of service to the poor as a critical function of the church because of what they say next in vv.3-7.