Musar sur Le Deutéronome 7:17

“Should you say to yourselves, ‘These nations are more numerous than we; how can we dispossess them?’ You need have no fear of them” (Deuteronomy 7:17-18).

This is the way this matter is explained in the book Ma'asseh Hashem on Deut. 7,17: "When you will say: "these nations are very numerous, how can I possibly drive them out?" G–d's answer was: "Do not be afraid of them" (verse 18), meaning that when you have these doubts and fears, what is meant is that if G–d were not to be on your side, you would have ample reason to think in those terms. When you rely on G–d, you will be fearless. If, however, you ascribe your success to your own efforts and prowess, then you will become very frightened when facing such people in battle. The word כי at the beginning of verse 17, is quite clear then and Rashi would not need to trouble himself to explain it as meaning "maybe." At any rate, this was G–d's purpose in authorising the despatch of the spies and His hope of strengthening the Jewish people's belief in Him. Moses, of course, had every reason to agree then. This is the reason that both G–d and Moses employ the term ויתורו as describing the function of the spies. This word is usually used when there is a concensus between the heart and the mind. An example is the last pragraph in the קריאת שמע, where we are warned לא תתורו אחרי לבבכם "not to follow your hearts."