"You shall keep My Sabbaths and reverence My sanctuary: I am the LORD."
This verse (above) is a powerful one to live by. Faith in and love for Christ always issues forth in two basic life parameters: celebration of the Sabbath (Sunday); and worship and service in the church (especially on Sunday).
The Christian life is designed to prosper and grow, "from glory to glory," (2 Cor. 3:18); and the way God achieves this is, "from Sabbath to Sabbath," (as it were). If God is "The LORD," as He says He is (at the end of the verse above), then He gets to "call the shots," and set the guidelines for His people. Let us benefit ourselves (and everyone else) by abiding faithfully within Christ's sheepfold.
[Puritan quote of the day: "Who shall despair when he is in Christ, who is complete?" --Richard Sibbes, in "Glorious Freedom"]