The doctrine of praying in tongues has long been one of the most discussed and debated subjects in the modern church era. For some, it is a cherished mark of the Pentecostal experience. For others, it is viewed with suspicion, discomfort, or even rejection. Yet controversy does not remove the subject from Scripture. If anything, the controversy is an invitation for believers to return to the scriptures and ask what the New Testament actually teaches. My argument in this paper is that praying in tongues is a legitimate and valuable gift for believers who are filled with the Holy Spirit. I want to argue that tongues function in the New Testament as an initial evidence of being filled with the Holy Spirit, though not the only evidence of a Spirit-filled believer. The primary focus of this paper is that praying in tongues is not merely a sign associated with the beginning of Spirit baptism, but an ongoing spiritual asset that benefits the believer in prayer, communion, edification, and intercession.