There are two parts to this instruction, the practical, intentional, deliberate aim of our thought life - "think on these things"... it means by extension "DONT think on those things". It is a simple exchange, this and not that, here and not there, these and not those... in other words, control the intake and focus of your mind. Turn off the TV, stop listening to the constant scream of our ruined culture and instead, turn your mind and thus your heart to things which are inherently good. Your soul will thank you! But the second part is what gives cold chills - what you learned, received, heard and saw IN ME - those things do. So the question for us is this... do I want anyone else living Christ just like me? If not, repent, re-think and re-aim. Live a life that displays God in truth, let your ways be what we see in those who are mature, and the God of peace will be with you... but more, BE that so that others may also find that God of peace!