It is likely David did, since he was a Jew.
All Sabbath-observers keep the Sabbath holy; and Hassidim are among them.
Remember the Sabbath day to keep it holy.
To keep the ordinances and commandments of God in keeping pure and spotless on sabbath day.
no
Yes. Exodus 20:8, " Remember the Sabbath day and keep it holy" (Wikipedia)
When the Pharisee reacted that Jesus violated the rules of the Sabbath, Jesus then told them about the time of King David. David and his men ate the food of the temple even it was only required for a priest.Abiathar the priest at that time allowed them because Yahweh allowed it. Jesus then told the Pharisee that the Sabbath was made for man not man for the Sabbath.
He has said that some of his favorite bands are The Doors, Black Sabbath, KISS, David Bowie, and Pink Floyd
The Seventh Day.
Not at all!
Remember the sabbath day, and keep it holy.
If you're Jewish and that matters to you, then you do.
That depends on which day is defined as the Sabbath, but generally no Christian church seems to keep it any more; the push of the outside world is too much.