They received a stern command. They were NOT to store manna for the next day. Nevertheless, some Israelites disobeyed, and the delightful food provided by God on one day was completely filled with maggots the next.
Herein lies a great Biblical truth. God has given you resources — money, talent, time, energy. Use it for God today. Don’t hold over for tomorrow because you might not get the chance. It might rot.
Too many Christians plan to give to God at some future date, whether their service or their offerings. Stop putting it off. Do it today. The suffering masses of humanity need to be reached today with the Good News. The need is not going to be more acute or chronic tomorrow (it will if you don’t give today what God has called you to give).