you walk everyday, and yet do you ever stop and think about what actually is going on while you're walking? if it weren't for the friction between your feet and the ground propelling you forward you wouldn't be able to go anywhere. Furthermore Newton's third law is greatly involved in the act of walking. Every step you take is responded by an opposite force coming from the ground, propelling you forward and giving you speed. this is why when you run you have to apply much more force to the ground in order to have a greater force pushed back at you.