Note 19 at 1 Cor. 14:15: Four different times in this verse, Paul said "I will." Once we have received this gift, speaking in tongues and interpreting that tongue is a decision of the will. Some people have mistakenly thought, "We do not have control over this gift. We can't speak in tongues when we want. We can't turn the Holy Spirit on and off." That's not the case.

It's not that we turn the Holy Spirit on and off at our will. He is always "on." We are the ones who are on and off. Anytime we will to do so, the Holy Spirit will give us the utterance to speak in tongues and the ability to interpret (see note 9 at Acts 2:4, p. 577).

Note 20 at 1 Cor. 14:15: "Praying with the spirit" and "singing with the spirit" are describing praying and singing in tongues. That is clear from the context. In the previous verse, Paul said when we pray in an unknown tongue, our spirit is praying. Notice also the use of the lower case "s" in the word spirit. That is identifying our spirit, not the Holy Spirit.