Some communities may prefer a less descriptive expression such as "you must be circumcised." (See: [[rc://en/ta/man/translate/figs-euphemism]])
## the sign of the covenant ##
"the sign marking the covenant" or "the sign that shows the covenant exists"
## the sign ##
Possible meanings are 1) “the sign” or 2) “a sign.” The first means that there was one sign, and the second means that there may have been more than one sign.