1 Corinthians 14:4: "He who speaks in a tongue edifies himself" 1 Corinthians 14:2: "For he who speaks in a tongue does not speak to men but to God, for no one understands him; however, in the spirit he speaks mysteries" 1 Corinthians 14:14: "For if I pray in a tongue, my spirit prays, but my understanding is unfruitful" Ephesians 6:18: "Praying at all times in the Spirit, with all prayer and supplication"