1 Corinthians 14:39

Wherefore my brethren, desire earnestly to prophesy, and forbid not to speak with tongues. But let all things be done decently and in order.

To prophesy ... While still refusing to forbid tongues categorically, for fear of wounding some with the real gift, Paul again stressed the superiority of teaching, commanding here that the brethren should desire to teach, not to speak in tongues.

Forbid not to speak with tongues ... Throughout this chapter, it has been stressed that the existence of actual gifts of tongue-speaking and interpretation made it impossible to declare all such things out of order. Despite this forbearance, there never was a church anywhere which could practice tongue-speakings while observing Paul's rules, which inevitably diminished them to the vanishing point; and which, after the cessation of miraculous gifts, eliminated them altogether.

Let all things be done decently and in order ... This is the golden rule for organizing and conducting public worship services of the church in all ages. The first announcement of it came in a situation where it was drastically needed; and, despite the fact that over-formalization may occur from an over-zealous enforcement of it, it is the failure to enforce it at all which distinguishes many so-called "free" religious groups today.