Any syncretism with the world will lead to confusion. We must separate from the world in terms of its religious practices and its false gospels.
We need the ability to discriminate in spiritual matters. Grace does not cover unrepented sins nor fellowship with those contemptuous of God's laws.
We face the same kind of pressures and stress that Timothy faced, with perilous times ahead of us, threatening the existence of the nation and the church.
The Christians in Corinth, known for its immorality, received Paul's first epistle around Passover time as a warning to overcome the affects of 'Sin City.'
Just as a dead person does no works, so a faith that does not include works is also dead. A person in whom living, saving faith exists will produce works.
The Sabbath is not a mere ceremonial observance, but identifies God's people as different, and consequently a perpetual irritant to the world.