I've always sort of wondered about this, why Christians believe the Sabbath is not to be followed but seem at the same time to look upon Sunday as a required day of worship and rest (with no work) instead.
Something that stems from the Biblical account of creation in which God rested on the seventh day.
How did the Sunday (first day) substitution for the seventh day Sabbath come about for (most of) Christianity and what is the Biblical basis of it?
Jesus kept the Sabbath, did he ever actually indicate that we are not to do the same?
Briefly,
@Frankj, when Jesus died on the cross, he abrogated external, national forms of the OT laws (Colossians 2:13-17), including the seventh day requirement. However, the inner principles of the laws still continue (rest and group worship on one day in seven). Two others are "You shall not murder," of which the inner principle is the protection of human life; and "You shall not commit adultery," of marriage.
Col 2:13 And you, who were dead in your trespasses and the uncircumcision of your flesh, God made alive together with him, having forgiven us all our trespasses,
Col 2:14 by canceling the record of debt that stood against us with its legal demands. This he set aside, nailing it to the cross.
Col 2:15 He disarmed the rulers and authorities and put them to open shame, by triumphing over them in him.
Col 2:16 Therefore let no one pass judgment on you in questions of food and drink, or with regard to a festival or a new moon or a Sabbath.
Col 2:17 These are a shadow of the things to come, but the substance belongs to Christ.
Furthermore, Paul explains that the old and new covenants are different:
2Co 3:5 Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God,
2Co 3:6 who has made us sufficient to be ministers of a new covenant, not of the letter but of the Spirit. For the letter kills, but the Spirit gives life.
2Co 3:7 Now if the ministry of death, carved in letters on stone, came with such glory that the Israelites could not gaze at Moses' face because of its glory, which was being brought to an end,
2Co 3:8 will not the ministry of the Spirit have even more glory?
2Co 3:9 For if there was glory in the ministry of condemnation, the ministry of righteousness must far exceed it in glory.
2Co 3:10 Indeed, in this case, what once had glory has come to have no glory at all, because of the glory that surpasses it.
2Co 3:11 For if what was being brought to an end came with glory, much more will what is permanent have glory.