Keeping the Sabbath was a big deal to the Jews. In Matthew 12:2 we see indignant Pharisees condemning Jesus and His disciples for picking spikes of grain on the Sabbath. Jesus reminds them of what King David and his band did when they were hungry. David's rightful place was at the kings table. But because of sin he was forced into exile and hiding. Under these circumstances it was perfectly acceptable for David and his men to eat the loaves of showbread.
Jesus' rightful position is reflected in His name. Jesus (God our Savior) Christ (anointed prophet priest and king). He is Lord of the Sabbath. He created the Sabbath and in Him we find rest for our souls.
Matthew 11:29 Take My yoke upon you and learn of Me, for I am gentle (meek) and humble (lowly) in heart, and you will find rest (relief and ease and refreshment and recreation and blessed quiet) for your souls. (AMP)
When we repent and trust in Jesus we are fulfilling the new testament definition of keeping the Sabbath.