John 5:19 is a key verse for the patristic and Reformation doctrine of the Trinity. Here Christ teaches that He does nothing from Himself because the Son is not from or of Himself. Jesus will state the same about the Spirit’s relation within the Trinity in John 16:13. He speaks as he is, and he is from the Father and the Son. Brenz summarizes thus (In D. Iohannis Ev., 85-86):
Quicquid enim pater facit, per filium, qui est Verbum, facit. Quicquid filius facit, a patre facit.
The Son works from the Father, and the Spirit speaks from both. Filioque