It was the Israelite people, not just Moses. God was reprimanding them after the events when the Scouts were sent to scout out the Holy Land. The Israelites did not exhibit complete trust in God (Deuteronomy ch.1). See Numbers ch.13-14.
The reason is given in Exodus 13:17-18.
they learned that God is with them in all of their bad,and good times
God provided for them (Exodus ch.16 and 17).
It was the route God chose for them to the Holy Land (Exodus ch.13).
What would it have taken to survive 40 years in the wilderness? Faith, believing that God the Father will provide every need for He provides even for the birds in the sky, imagine how much He must care for us. And also hope, knowing that one day God will bring the Israelites out of the wilderness with victory.
The Torah is the Five Books of Moses, dictated to him by God during the Israelites' sojourn in the wilderness.
Forty years (Numbers ch.14)
God sent fiery serpents as a punishment for the Israelites' disobedience in the wilderness. These serpents bit the people, causing many deaths until Moses made a bronze serpent on a pole, which the people could look at to be healed.
God provided the manna (Exodus 16).
Moses (Exodus 32:34), by the guidance of God (Numbers ch.9).
The sweet bread provided in the wilderness was called manna.
The number of israelites killed in the wilderness were many. as the bible says the entire generation of people who made the golden calf walked and died in the wilderness.
Moses.