Among Jews the rite of circumcision takes precedence over any other institution or observance. Zimmerman believes it was through this rite that the ancient Hebrews sought reassurance that death was not annihilation and the utter end of all. The circumcised penis, with its exposed glands, resembles the uncircumcised penis in erection when the head of the penis is disclosed and the foreskin retracted. 'A circumcised penis is a copy of a penis in erection', therefore it symbolizes potency and fertility, and in this way 'ensures' the continuity of one's self through one's sons and sons' sons.