I have a “bombshell” for the contributors of this topic to consider, to the intent of Paul, “Let every man be fully persuaded” Rom 14:5.
It mattered to Paul and after his conversion, he spent 3 years in Arabia studying (Gal 1:17,18) but blind & naked Laodicea has accepted a papal calendar that changed everything and we are not fully persuaded because we haven’t looked carefully at the “law,” a word in the title of this article that overlooks its Bible origin, torah–five books.
The 7th day Sabbath was counted from the New Moon in Bible times in contrast to the papal calendar that gives us months with NO relationship to the new moon, but an unending series of 7’s. The biblical proof is big.
In Lev 23, we see the 1st day of Passover was the 15th day of the month, a Sabbath, called a “high day” in John 19:31 when the 7th day Sabbath and the Passover coincided. The 16th was the wave sheaf corresponding to “Sunday” when Christ was the 1st fruits of the dead.
But the point is, the Sabbath (Lev 23:11, Strong’s shabbat, 7676) was on the 15th day, COUNTED from the New Moon, as seen in Exod 12:2, seen as a thin crescent and they were to blow the trumpet in the new moon, Ps 81:3.
That does not seem huge until we realize the first place we find the word “Sabbath” is in Exod 16, in the SECOND month when it is ALSO on the 15th & 22nd of the month (see verses 1,4,5,22,23).
To have two months in a row with a 7th-day Sabbath on the 15th & 22nd means they were counting every 7th day from the new moon which was also in a position like a Sabbath. After the new moon they worked six days and the 7th day fell on a calendar under the New Moon day as #8, 15, 22, and 29.
There are other Bible examples of these numbers, BUT NOWHERE can you find a Sabbath on any other numbered day, OR I will give you $100 to disprove what some call the lunar calendar or creation calendar.
I had a website with 10 reasons why it was “luny” until a friend showed me the two months in a row. You can’t have Sabbath on the 15th & 22nd two months in a row unless you are counting from the New Moon.
The papal calendar we follow is a masterpiece to destroy bibiical practice and the Jews accepted it under Hillel or some leading rabbi.
The Peshita Translation of Rom 14:5 is helpful-- “He who is mindful concerning a day’s duty is considerate of his master; and every one who is not mindful concerning a day’s duty, is inconsiderate of his master. And he who is wasteful, is detrimental to his master even though he confesses it to God; and he who is not wasteful, is not wasteful to his master, yet he likewise tells it to God.”