Rashi on Leviticus 23:5/רש"י על ויקרא כ״ג:ה׳

1בין הערבים AT EVENTIDE — i. e. the period from six hours onwards (reckoning from six o’clock in the morning) (Sifra, Emor, Chapter 11 1; cf. Rashi on Exodus 12:6).

2פסח לה׳ [AT EVENTIDE] IS THE פסח OF THE LORD — i. e. the offering of the sacrifice which bears the name פסח‎.