Don't be selfish to your brother and make him cry, share with him and stop fighting or you'll get in trouble.
I'll get in trouble if I make my brother cry.
Here you go, you can play with it.
At this age, your toddler realizes that others have rights and needs as well. However, he is yet to grasp the difference between right and wrong. An aged 2-3toddler might show empathy-based guilt and moral behaviors. Depending on the actions conveyed by parents, the toddler understands obedience is the norm.
Your toddler knows that it is wrong to take away a toy from a sibling only because he might land himself in trouble. While he may not understand or clear why making his brother cry is wrong, he knows that he will be punished for doing that.
Positive punishment was applied, it is a disciplining method that focuses on reducing a certain undesired behavior in the child by applying a negative consequence to it. This is why the toddler tends to follow the rules to avoid punishment and toddler expects older people, or parents, to take charge.