When Paul addressed the Jerusalem mob in Acts 22, he confessed that in his pre-conversion life he had “persecuted this Way to the death” (22:4). “This Way”? What is that? On his way to 
Damascus in Acts 9, he was planning to find and persecute “any who were of the Way” (9:2). “The Way”? Who are they? That was the Holy Spirit’s way of depicting those in the first century who were faithful followers of Christ (cf. Acts 19:9, 23; 24:14, 22). The singularity of the word (not “Ways”) emphasizes the exclusive and unique nature of God’s followers. Only one group!
Elsewhere, Paul specifically stated that he “persecuted the church” (1 Cor. 15:9; Gal. 1:13; Phil. 3:6). Compare these two affirmations: Paul persecuted “the Way” and Paul persecuted “the church.” “The Way” consisted of faithful followers of Christ, and there was only one. “The church” also consisted of faithful followers of Christ, and there also was only one. The singularity of both words emphasizes their exclusive and unique nature! There is only one church as there is only one Way!