Need MAJOR advice?

Ok so my older bigger neighbor with br knuckles who could beat me in 1 hit (he's 15 im barely 13). he told me he smokes/dubee/pot and he said before school ends i will smoke with him, i really don't want to because my religion (christianity) says not to (which i found out today he doesn't believe in anything) and not only that i don't want to get hooked and blow all my money on it, i don't want to see him anymore yet he comes over everyday to play bball, he gets mad easy, how do i tell him to go away without getting him mad