first month: called in Pentateuch "Abib" (Exodus 13:4; Exodus 23:15; Exodus 34:18; Deuteronomy 16:1); and "Nisan" in later books (Nehemiah 2:1.Esther 3:7; Esther 3:7). about beginning of April.
at even: any time from sunset of one day till sunrise of the second day. Hebrew "between the evenings".
the LORD'S [Hebrew. Jehovah. s]
passover. This is the first of the Feasts; Tabernacles is the seventh. First, redemption; last, rest. Redemption is the title to rest.