Palm Sunday marks the first day of a holy and great eight-day week
During a feast of Passover in Jerusalem, Christ was crucified on a Friday, and he rose from the dead on the third day.
These three paschal days, from the beginning of the Friday Christ was crucified to the end of the Sunday on which he rose from the dead, are called Triduum Paschale.
The third day of Triduum Paschale marks the last day of a new week.
- The old week is the period of seven days from sunset Saturday to sunset Saturday.
- The new week is the period of seven days from midnight Sunday to midnight Sunday.
In the old week, Sunday is the first day (post sabbatum).
In the new week, Sunday is the seventh day (post dominicam).
The Bible says:
"And you shall count for yourselves from the day after the Sabbath, from the day of your bringing the wave offering’s sheaf—there shall be seven full weeks. Until the day after the seventh Sabbath you shall count fifty days". (Leviticus 23:15-16 LEB)
In other words, seven full weeks, or fifty days, from the beginning of the day following a Sabbath to the end of the day following the seventh Sabbath.
The eighth day
Palm Sunday marks the first day of a holy and great eight-day week.
The last day of the holy and great eight-day week is the eighth day.
The eighth day is: (i) the third day of Triduum Paschale, (ii) the last day of the holy and great eight-day week, (iii) the first day of the count to Pentecost.
The count to Pentecost (1–50) is the eighth day plus seven full weeks (1+(7x7)=50).
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