Since 1 Nisan A.D. 30 was a Friday, the tenth of Nisan was a Sunday, and this was the day the passover lamb was selected. This was the day of the triumphal entry, nowadays known as Palm Sunday.
Jesus followed the law of Moses and held the Passover meal after sunset on the 14th of Nisan, which would make it Wednesday night. The official sacrifice of the Passover lamb and the release of the scapegoat was not going to happen until afternoon of the 14th of Nisan, or about 20 hours later.
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