16 For this reason the Jews persecuted Jesus, and sought to kill Him, because He had done these things on the Sabbath.
This verse launches a discourse by Jesus on the relationship between Him and the Father that extends to the end of the chapter (Jn 5:17ff).
16 For this reason the Jews persecuted Jesus,
Jesus’ statement in verse 17 launches the first overt and open hostility against Him. They now come to question Jesus as to why He violated the Sabbath.
and sought to kill Him,
The Jews even took the extreme action of attempting to kill Jesus.
because He had done these things on the Sabbath.
Jesus conflicted with the leaders of His day over the Sabbath in several places (chapter 9; Mr 2:23-28; 3:1-5; Lu 13:10-17; 14:1-6). Our Lord clearly had a different view of His right to heal on the Sabbath than the prevailing view of His day. Jesus performed 36 miracles and performed seven of these on the Sabbath.
Keeping the Sabbath mingles law with grace.
The Sabbath was enjoined solely on Israel, not the church. Retrospectively, for Israel, the Sabbath looked back and memorialized God’s creation undisturbed by sin. Prospectively it pointed to the Millennial reign of Christ (Is 11:10–16: 60:1–22; Acts 1:6; Ro 11:26–36). God put the Sabbath in abeyance during the church age because of Israel’s unbelief.
It is not biblical to mingle law with grace. If we attempt to keep the Sabbath we do indeed mix law with grace. We are people of grace since the church began. The law came by Moses but grace and truth came by Christ.
Reversion to living under the law detracts from the glory of the risen Christ. Under Christ we live under grace; under the law we live legalistically, which is the yoke of bondage.