Arcana Coelestia #2110
2110. 'When he was circumcised in the flesh of his foreskin' means purification. This is clear from the meaning of 'being circumcised' as being purified from self-love and the love of the world, dealt with in 2039, and from the meaning of 'flesh of the foreskin' as the removal of those loves, dealt with in 2041, 2053, 2057.
Arcana Coelestia #2042
2042. 'And it will be a sign of the covenant between Me and you' means that which is a representative and a meaningful sign of purity. This is clear from what has been shown just above in 2039, to the effect that circumcision was no more than a representative of purification from filthy loves. And because it was merely an external religious ceremony that represented and meant what was internal it was not the covenant but a sign of the covenant.