The answer
Simply because this is a Biblical commandment from the Old Testament, and we have followed this commandment as is. It is also to remind us of the original sin which began with Eve tempting Adam with the apple. However, we must not forget that if we fell by the first Eve, we are saved through the second Eve, who is our beautiful mother St. Mary, because she gave birth to our Saviour and Redeemer.
H.G. Bishop Moussa