Romans 14:1  As for the man who is weak in faith, welcome him, but not for disputes over opinions (RSV), disputable matters (NIV), doubtful disputations (KJV)

Ro 14:5,6 - One person esteems one day above another; another esteems every day alike. Let each be fully convinced in his own mind. ⁶He who observes the day, observes it to the Lord; and he who does not observe the day, to the Lord he does not observe it. He who eats, eats to the Lord, for he gives God thanks; and he who does not eat, to the Lord he does not eat, and gives God thanks.  (Tolerance of others)

Galatians 4:9-11 - But now after you have known God, or rather are known by God, how is it that you turn again to the weak and beggarly elements, to which you desire again to be in bondage? ¹⁰You observe days and months and seasons and years. ¹¹I am afraid for you, lest I have labored for you in vain.

Colossians 2:16,17 - So let no one judge you in food or in drink, or regarding a festival or a new moon or Sabbaths, ¹⁷which are a shadow of things to come, but the substance is of Christ.

Verse 16 Sabbaths or Sabbath-day, Strongs 4512 (sabbaton) day of weekly repose from secular avocations

Verse 17 shadow, Strongs #4639 (skia) shade or a shadow (literally or figuratively [darkness of error or an adumbration]) shadow

Adumbrate Websters Collegiate Dictionary -  to foreshadow vaguely: intimate to give a sketchy representation or outline or to suggest or disclose partially overshadow, obscure

Notice in verse 17 the things that are a shadow of things to come or as in some translations is coming, however, at the time Paul wrote this Christ had already come once and died for us it must be speaking of His next coming that Paul is writing to the Colossians about.