Romans 14:5-6, Is Shabbat a Personal Choice?

Let every man be fully persuaded...

Romans 14:5-6, One person esteems one day over another while another judges every day alike. Let each be fully convinced in his own mind. The one who observes that day does so to the Lord...

At first glance this passage could be used to argue that keeping Shabbat would be a matter of choice, one that each person should make up their own mind of. However, there are several points to consider:

Now, just as Romans 14:5 doesn't mention Shabbat in the verse, it also doesn't say that these are fast days. However, when we read the context, the context of eating and abstaining is clearly declared. Notice:

^{Romans 14:1-23} Now accept the one who is weak in faith, but not for the purpose of disputes about opinions. ² One person has faith to eat anything, but the weak eats only vegetables. ³ Don’t let the one who eats disparage the one who does not eat, and don’t let the one who does not eat judge the one who eats, for God has accepted him. ⁴ Who are you to judge another’s servant? Before his own master he stands or falls... ⁵ One person esteems one day over another while another judges every day alike. Let each be fully convinced in his own mind. 6 The one who observes that day does so to the Lord. The one who eats, eats to the Lord, for he gives thanks to God; and the one who abstains, abstains to the Lord, and he gives thanks to God... ¹³ Therefore let us not judge one another from now on, but rather decide this—not to put a stumbling block or a trap in the way of a brother. ¹⁴ I know, and am persuaded in the Lord Yeshua, that nothing is unholy in itself; but it is unholy for the one who considers it unholy. ¹⁵ For if your brother is grieved on account of food, you are no longer walking according to love. Do not destroy by your food the one for whom Messiah died. ¹⁶ Therefore do not let what is good for you be spoken of as evil— ¹⁷ for the kingdom of God is not about eating and drinking, but righteousness and shalom and joy in the Holy Spirit. ¹⁸ For the one who serves Messiah in this manner is pleasing to God and approved by men. ¹⁹ So then let us pursue what makes for shalom and for the building up of one another. ²⁰ Stop tearing down the work of God for the sake of food. Indeed all things are clean, but wrong for the man who by eating causes stumbling. ²¹ It is good not to eat meat or drink wine or do anything by which your brother stumbles. ²² The faith you have, keep it to yourself before God. How fortunate is the one who does not condemn himself for what he approves. ²³ But the one who has doubts is condemned if he eats, because it is not of faith. And whatever is not of faith is sin.

There is no contextual reason to read Shabbat into this verse, whereas it makes perfect sense to understand "observes that day" as one that is specifically related to food. The context does not give us any indication which fast this is referring to, outside of it being one that God didn't instruct. With this said, there are two different fasts this could be referring to:

Weekly Fasts

The Pharisees fasted on Mondays and Thursdays, note Yeshua's parable:

^{Matthew 9:14-15} Then John’s disciples came to Him, saying, “Why do we and the Pharisees fast often, but Your disciples do not fast?” ¹⁵ And Yeshua said to them, “The guests of the bridegroom cannot mourn while the bridegroom is with them, can they? But the days will come when the bridegroom is taken away from them, and then they will fast.

^{Luke 18:9-14} Then Yeshua spoke this parable to some who trusted in themselves that they were righteous, while holding others in contempt. ¹⁰ “Two men went up to the Temple to pray, one a Pharisee and the other a tax collector. ¹¹ The Pharisee stood and was praying this to himself: ‘O God, I thank You that I am not like other people—thieving, unjust, adulterers, or even like this tax collector. ¹² I fast twice a week and tithe on all that I get.’ ¹³ “But the tax collector, standing some distance away, wouldn’t even lift his eyes toward heaven, but beat his chest, saying, ‘God, be merciful to me, the sinner!’ ¹⁴ I tell you, this man, rather than the other, went down to his home declared righteous. For everyone who exalts himself will be humbled, but the one who humbles himself will be exalted.”

The Didache, a book written approximately a decade after Romans was written says thus:

^{Didache 8:2} Let not your fasts be with the hypocrites, for they fast on Mondays and Thursdays, but do you fast on Wednesdays and Fridays.