Leviticus 23:5

In the fourteenth [day] of the first month
The month Nisan, the same with Abib, the month in which the children of Israel came out of Egypt, for which reason it was made the first month in the year, answering to part of our March and part of April; and for the same reason was the passover kept at this time, as follows: at even [is] the Lord's passover;
that is, that was the time for the keeping the passover, even "between the two evenings", as it may be rendered; from the sixth hour and onward, as Jarchi, trial is, after noon or twelve o'clock the middle of the day, as Gersom, when the sun began to decline; (See Gill on Exodus 12:6).