Rashi on Exodus 13:17/רש"י על שמות י״ג:י״ז

1ויהי בשלח פרעה... ולא נחם AND IT CAME TO PASS WHEN PHARAOH HAD SENT [THE PEOPLE AWAY] THAT GOD GUIDED THEM NOT — The word נחם means He guided them, just as, (Exodus 32:34) “Go, guide (נחה) the people”, and (Proverbs 6:22) “when thou goest it shall guide (תנחה) thee”.

2כי קרוב הוא BECAUSE IT WAS NEAR, and it would therefore be easy to return by the same route to Egypt. — Of Midrashic explanations there are many (cf. Mekhilta).

3בראתם מלחמה WHEN THEY SEE WAR — For instance the war mentioned in (Numbers 14:45) “Then the Amalekites and the Canaanites came down etc.” If they had proceeded by the direct route they would have then turned back. This is evident, for what would have been the case? If, when He led them about by a circuitous way, they said, (Numbers 14:4) “Let us appoint another chief and go back to Egypt”, had He led them by a direct route how much the more certainly would they have spoken so.

4פן ינחם PERADVENTURE [THE PEOPLE] REPENT — peradventure they cherish a different thought (they change their mind) about having gone out and set their hearts on returning (cf. Rashi on Genesis 6:6).