Bible Verses About Prayer: should be offered Up with the Spirit and Understanding

Ye worship ye know not what: we know what we worship: for salvation is of the Jews.

But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him.

God is a Spirit: and they that worship him must worship him in spirit and in truth.

What 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.