what am I doing wrong.

so my son Marley. is 4 will be 5 in September. but he won't listen to anything I say. actually no one. Im so frustrated. for example Marley please hold my hand while we cross the road. he stops right in the middle of the road and starts throwing a fit. or I ask him to help me clean up the game we were play. he says no and spits and hits me. IDK what I'm doing wrong. I'm trying to work with him on please and thank you. we have a daily routine. :(