Rashi on Exodus 12:11/רש"י על שמות י״ב:י״א

1מתניכם חגרים YOUR LOINS GIRDED — i. e. prepared for the journey (Mekhilta).

2בחפזון — This is an expression denoting hurry and haste, similar to, (I Samuel 23:26) “And David made haste (נחפז) to get away”; (2 Kings 7:15) ”which the Arameans had cast away in their haste"

3פסח הוא לה IT IS THE PASSOVER OF THE LORD — The offering is called פסח in allusion to the springing and passing over — because the Holy One, blessed be He, passed over the houses of the Israelites in between the houses of the Egyptians and sprang from Egyptian to Egyptian, whilst the Israelite who was between them escaped. The words “And ye shall eat it in haste for it is a 'springing’-offering to the Lord” imply: Ye, therefore, do every act of sacrificial service connected with it (with the Paschal lamb) in honour of Heaven (God) by way of springing and leaping over (i. e. hastily), as a reminder of its name, which is called, the “springing”-offering. In old French, (Provencal) too, Pascua (the term for the Passover festival) signifies stepping over.