Rashi on Exodus 23:15/רש"י על שמות כ״ג:ט״ו

1חודש האביב THE MONTH OF אביב — it is the month when the grain becomes full in its ripe state (באביה). The word אביב is connected with אַב which signifies maturity, and being the first of the fruit to ripen (cf. Rashi on Exodus 9:31).

2ולא יראו פני ריקם AND NONE SHALL APPEAR BEFORE MY FACE EMPTY — When you come to appear before My face on the festivals, bring Me burnt-offerings (Mekhilta; Chagigah 7a).