Classical Pentecostals typically affirm that “the initial evidence of the baptism in the Holy Spirit is speaking in other tongues as the Spirit gives utterance.” I frequently encounter Christians, including those from Pentecostal churches, who misunderstand the intent of the “initial evidence” doctrine.
Some people object to the initial evidence doctrine by saying that there are other possible evidences, such as righteous living, empowered witness, engaging in the spiritual gifts, and other signs of the Spirit’s work. However,
1. The initial evidence doctrine does NOT mean that tongues are the only evidence of baptism in the Holy Spirit.
Rather, the “initial” statement indicates that there could, and indeed should, be subsequent evidence such as those listed above. If tongues are the only evidence then the “initial” qualifier would be unnecessary. On this, see my previous post, “Tongues is NOT the Only Sign of Spirit Baptism.” Furthermore,
2. The initial evidence doctrine does NOT mean that baptism in the Holy Spirit is only about gaining the ability to speak in tongues.
Rather, Classical Pentecostals generally emphasize that those who are baptized in the Spirit receive power for witness (Acts 1:8). Finally,
3. The initial evidence doctrine does NOT mean that Christians who have not spoken in tongues do not have the Holy Spirit dwelling within them.
Rather, on their best days, Classical Pentecostals affirm that all Christians receive the Spirit when they place their faith in God and that the Spirit will be active in their lives in many different ways, whether or not they speak in tongues.
 The Pentecostal Assemblies of Canada, Statement of Fundamental and Essential Truths, 2014, available online at https://paoc.org/docs/default-source/paoc-family-docs/what-we-believe/statement-of-fundamental-and-essential-truths.pdf?sfvrsn=6.