The Feast of the Passover: Commenced the Fourteenth of the First Month at Even
Source: TTT
Exodus 12:2, 6, 18
“This month is the beginning of months for you; it shall be the first month of your year. / You must keep it until the fourteenth day of the month, when the whole assembly of the congregation of Israel will slaughter the animals at twilight. / In the first month you are to eat unleavened bread, from the evening of the fourteenth day until the evening of the twenty-first day.
Leviticus 23:5
The Passover to the LORD begins at twilight on the fourteenth day of the first month.
Numbers 9:3
You are to observe it at the appointed time, at twilight on the fourteenth day of this month, in accordance with its statutes and ordinances.”