M.P.
I suggest that taking every thing away only teaches him that it's OK to take things. The consequence related to the action can have better results.
How old is your son? If he's in the lower grades (ages 4- 10 or so) "stealing" is fairly common because they may have not grasped the concept of ownership. In the 2nd grade I took a classmate's notebook home. My mother talked with me about how t he notbook belonged to this other child and how would I feel if someone took one of my things. I told her I took it because I liked it. She told me to ask her about buying one for myself. Then she took me to school where I gave back the notebook and apologized. This lesson gave me something to do about my wish for things and how I could have some things just by asking. I never took anything, as far as I remember, since. I remember asking another child if I could have something belonging to her. If shE said no, the transaction reinforced ownership.
My daughter took something from a store. I took her in to give the object back and apologize. Sue was in the 2nd grade. We talked about what belongs to us and what belongs to someone else several times.
Neither my mom or I punished our children for taking thst which dprs not belong to us. We talked in a stern but loving way about why we took things; about ownership and how to get things we wanted. My family was poor and parent's talked a lot about the lack of money to buy things. I learned to tell my mother what I wanted. She then said yes or no. I also learned I could ask friends for what they had. Again, yes or no. Respect the answer. Our teacher helped me talk with my friend.
I was relieved that my mother would help me. I trusted my mom to love me and help me work out a way to right the wrong. She didn't lecture me. She didn't punish me. She taught me right from wrong while allowing me to feel good about myself.
Taking something that does not belong to us with a young child is not stealing in the same sense as it would with an older child who does understand the concept of ownership. Thinking that stealing is starting the path to breaking the law and feeling you have to punish him because this is serious only teaches him he doesn't want to upset you again. He wwill have not learned that he's OK and how his decision got him in this mess. Or why taking the cards is wrong.