ABC:Isaiah 1

Verse 13, Should We Keep the Sabbath?
Dan Barker of FFRF claims there is a contradiction here and makes the following comments (italicized):

Shall We Keep the Sabbath? Exodus 20:8 Remember the sabbath day, to keep it holy. Exodus 31:15 Six days may work be done; but in the seventh is the sabbath of rest, holy to the LORD: whosoever doeth any work in the sabbath day, he shall surely be put to death. Numbers 15:32 And while the children of Israel were in the wilderness, they found a man that gathered sticks upon the sabbath day. 36 And all the congregation brought him without the camp, and stoned him with stones, and he died; as the LORD commanded Moses. vs. Isaiah 1:13 Bring no more vain oblations; incense is an abomination unto me; the new moons and sabbaths, the calling of assemblies, I cannot away with; it is iniquity, even the solemn meeting. John 5:16 And therefore did the Jews persecute Jesus, and sought to slay him, because he had done these things on the sabbath day. Colossians 2:16 ¶ Let no man, therefore, judge you in meat, or in drink, or in respect of an holy day, or of the new moon, or of the sabbath days:

The FFRF want to focus on the Sabbath rules under the Old Covenant, not the New Covenant which Christians are under (Jeremiah 31:31); ignoring the context of the Sabbath for which it was given, as the Israelite Pharisees did. In doing so, they ignore the principles emphasized in the New Testament by Jesus about the Sabbath, that it was intended primarily for the good of people, not as a burden. (Mk. 2:27) What matters is that the Sabbath be used to do good for others. (Mt. 12:12)

The Sabbath was intended to protect the poor from overwork, not create onerous regulations that govern what everyone can do on a certain day of the week (as the Pharisees viewed it). The Old Testament Covenant, including its rules on the Sabbath, was not kept properly by the Israelites for thousands of years, which is why Jesus brought in the New Covenant which emphasizes the underlying spiritual principles the Sabbath was intended for; protecting and helping mankind while focusing on God.