He that searcheth (ο εραυνων). God (1. Samuel 16:7).

According to the will of God (κατα θεον). See 2. Corinthians 7:9-11 for this phrase κατα θεον (according to God). The Holy Spirit is the "other Paraclete" (John 14:16) who pleads God's cause with us as Christ is our Paraclete with the Father (1. John 2:1). But more is true as here, for the Holy Spirit interprets our prayers to God and "makes intercession for us in accord with God's will."