Jesus was always a Jew. The religion he belonged to practiced circumcision, not the one he founded. If the two belief systems were identical, then one would have been superfluous to requirement. And also Christianity had an alternative to it and that was baptism. Which ironically was practiced by John The Baptist before Christianity came into existence. And the laying of water on skin was also symbolic in Judaism. Jesus himself both had his own feet washed and washed others' too.
A MIND IS LIKE A PARACHUTE : IT DOES NOT WORK UNLESS IT IS OPEN