Rashi on Leviticus 23:11/רש"י על ויקרא כ״ג:י״א

1והניף AND HE SHALL WAVE [THE OMER] — Every form of the root נוף used in connection with sacrifices signifies that one moves the latter about both horizontally (מוליך ומביא) and upwards and downwards (מעלה ומוריד); he moves it about horizontally to prevent (i. e. the act was symbolical of preventing) destructive winds, he moves it about upwards and downwards to keep away injurious dews (cf. Rashi on Exodus 29:24) (Menachot 62a).

2לרצנכם TO BE ACCEPTED FOR YOU — If you offer it according to this precept it shall effect favourable acceptance for you.

3ממחרת השבת ON THE MORROW AFTER THE DAY OF REST [THE PRIEST SHALL WAVE IT] — This must mean on the morrow of the first day of the Passover festival (on the 16th of Nisan); for if you say that it means on the morrow of the weekly Sabbath (i. e. on a Sunday) you do not know which particular Sabbath Scripture is referring to (Menachot 66a).