When we pray in the spirit, we do not speak to humans, but to God, and it is our spirit that prays whilst the mind is unfruitful. When we speak in a tongue, in our spirit we speak secrets/mysteries. The bible says that this is a way to edify our self, and the Greek word for “edifies” is oikodomei, which means ‘home-building’.
Praying in the soul– “What is the outcome then? I shall pray with the spirit and I shall pray with the mind also; I shall sing with the spirit and I shall sing with the mind also.”- 1 Corinthians 14:15
Praying with the mind/understanding is a way to “abound for the edification of the church”, since the brethren will be able to understand the speech. Paul the apostle desired to speak five words with his mind, that he may instruct others also, rather than ten thousand words in a tongue.
Praying in the body- “And when he had said these things, he knelt down and prayed with them all.”- Acts 20:36
Expressing ourselves in prayer to God through our body has always been practiced in God’s congregation. In Solomon’s prayer of dedication, Solomon “spread out his hands toward heaven”. Paul urges: “Therefore I want the men in every place to pray, lifting up holy hands, without wrath and dissension.” (1 Timothy 2:8)