but it was this day, the 10th, that it was to be declared to be THE LAMB, the one they would sacrifice and eat.
Corresponds to the Song of Assent, Messianic prophecy of the triumphant entry, "This is the day the Lord has made, let us rejoice and be glad in it". THE DAY was Sunday where Jesus finally allowed himself to be worshipped as king and told the religious leaders who complained of the blasphemy that if the people held their peace on THAT DAY, the rocks would cry out. This was on Sunday the 10th. He was crucified on Good Thursday afternoon the 14th, Passover. The next day Friday was the first day of the Feast of Unleavened, another sabboth, and Saturday was as you said the normal Sabboth. He then rose on the 3rd day, Sunday morning.
During the week Jesus lamented over the city of Jerusalem and said because they did not understand bible prophecy predicting his triumphal entry to Jerusalem on "THAT DAY", Sunday, Jerusalem would be destroyed, because they "knew not the day of their visitation", referring to the prophecy of "This is the day the Lord has made" on that Sunday, prophesied by Daniel to be 483 years to the day from the day commandment was given to rebuild Jerusalem in Daniel 9:25 at the end of the Babylonian captivity:
Know therefore and understand, [that] from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince (the Sunday of his triumphal entry when he would present himself as the Meschiach, or Messiah, of Israel) [shall be] seven weeks, and threescore and two weeks: the street shall be built again, and the wall, even in troublous times.
Seven weeks (of years) and threescore and two weeks (of years) = 69 x 7 = 483 years from the day of the commandment to restore and rebuild Jerusalem at the end of the Babylonian captivity to Palm Sunday on the 10th of Nisan, 32AD.