Another reason we should covet tongues is for powerful and effective prayer. In 1 Cor 14:14, Paul indicates that when we pray in a tongue, our spirit prays but our mind is unfruitfull. In light of what He says in Romans 8:26-27, this is a good thing in that our mind is unable to influence us to perhaps pray against the will of God. In that passage, Paul states: "In the same way the Spirit also helps our weakness; for we do not know how to pray as we should, but the Spirit Himself intercedes for us with groanings too deep for words; and He who searches the hearts knows what the mind of the Spirit is, because He intercedes for the saints according to the will of God. (NASB) Although Paul states that he will, pray and sing with his mind he will also pray and sing with his Spirit. How wonderful it is to know that when we pray in the Spirit, we can know that the Spirit is praying the perfect will of God through us.
Lastly, praying in the Spirit allows us to go on the offensive in spritual warfare (Ephesians 6). According to Jude 1:20-21 it also is associated with buiding ourselves up in our most holy faith and keeping us in the love of God. These are just a few reasons that Paul cautions the church not to forbid speaking /praying in tongues but to be shure that it is done properly and in an orderly manner (1 Cor 14:40).