Question On The Parsha

1] Rashi says that Hashem told Moshe שלח לך - לדעתך, it's up to you to decide whether you want to send spies. Why did Hashem leave the decision up to Moshe? If it is the right thing to do he should be commanded and if not then he should be told to refrain?!

We find elsewhere that part of capturing the land was by sending spies with the command of Hashem [Yehoshua 2/1, Shoftim 7/7], so why was it different over here?