Deut 17 God knew the Israelite kings would lose sight of Him because most of their wants were selfish. That is why God gave the king some parameters to keep their focus heavenward, not here on earth. Like the king, the Israelites were not satisfied with just manna. They wanted meat a.k.a. horses, women, and money. That is why God reminded them to not multiply them.
When Jesus came on the scene, people were looking to be fed what the world would give rather than the Bread of Life come down from heaven. In fact, while Jesus served here on earth, he often asked, “What do you want me to do for you?” Not one responded I want to be more like you. Not one responded, “The Lord is my Shepherd; I lack nothing.” Not one responded I am more blessed to give than receive.
It is not wrong to ask God for things because He is our heavenly Father; “All generous giving and every perfect gift is from above, coming down from the Father of lights, with whom there is no variation or the slightest hint of change.” [James 1:17] God does tell us to ask for His provision in our life as well as other things. However, when we ask with wrong motives, so we may spend it on our selfish pleasures; God is not pleased. [James 4]
Are you prepared to ask God what He wants for you and not what you want? Is your heart right before God as you enter your closet to pray?