And he that searcheth the hearts knoweth what [is] the mind of the Spirit, because he maketh intercession for the saints according to [the will of] God.
Note 6 at Ro 8:27: "He that searcheth the hearts" is a reference to God. God knows our hearts, and He knows that the Holy Spirit will only intercede for the will of God to be done. The Holy Spirit is never at a loss as to how to convey our needs to the Father, as we sometimes are. That's the reason this ministry of the Holy Spirit is so important. There is such oneness between the Father and the Holy Spirit that even His groanings are perfectly understood.