Even lifeless instruments like the flute or the harp must play the notes clearly, or no one will recognize the melody. And if the bugler doesn’t sound a clear call, how will the soldiers know they are being called to battle? It’s the same for you. If you speak to people in words they don’t understand, how will they know what you are saying? You might as well be talking into empty space.
Well then, what shall I do? I will pray in the spirit, and I will also pray in words I understand. I will sing in the spirit, and I will also sing in words I understand. For if you praise God only in the spirit, how can those who don’t understand you praise God along with you? How can they join you in giving thanks when they don’t understand what you are saying? You will be giving thanks very well, but it won’t strengthen the people who hear you. (1 Corinthians 14:7-9, 15-17 NLT)