Is it a command from the Lord not to forbid speaking in tongues?
Yes. The instruction not to forbid speaking in these languages is identified as a commandment from the Lord Himself. The same context connects it with desiring to prophesy and speak forth the Word before the printed Word came, while verse 40 still requires all things be done decently and in order.
Les explains that the verse says, “Wherefore, brethren, covet or desire to prophesy, to speak forth the Word, because the printed Word hasn't come yet, and forbid not to speak in these languages.” He adds, “Nor will I, because of this verse. It's a commandment from the Lord Himself not to forbid the use of languages.” But he immediately moves to verse 40: in the local congregation, all things must be done decently and in order, because that brings honor and glory to the God we claim to worship. He warns against taking these things out of context and forgetting that the primary purpose of all we do is to bring honor and glory to God.
Wherefore, brethren, covet to prophesy, and forbid not to speak with tongues.
More Questions
Is it wrong to forbid speaking in tongues in church?
Verse 39 contains a commandment from the Lord Himself not to forbid the use of tongues/languages, which is why Les says he will not forbid it.
Where does the command not to forbid tongues come from?
The command not to forbid the use of languages is a commandment from the Lord Himself.