1 Corinthians 14:15 says:
15So what should I do? I will pray with my spirit, but I will also pray with my mind. I will sing with my spirit, but I will also sing with my mind. (Easy-to-Read Version)
King James Version: 15What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.