A personal name in a religious tradition is rarely just a label. It is usually a statement about lineage, obligation or hope, and the ceremony that confers it is the moment those claims are made in front of witnesses.
Sikh practice makes the point most sharply. The family brings the infant to the gurdwara, the Guru Granth Sahib is opened at random, and the first letter of the first word on the page becomes the first letter of the child's name. The parents choose the name; the scripture chooses the constraint. Then Singh is added for a boy and Kaur for a girl, and these are not middle names. They were introduced to displace the caste surname, which in Punjabi society announced a family's standing in the first syllable. The naming rite therefore performs a small act of levelling every time it is used.
Hindu namakarana works in the opposite direction, tying the name to the individual rather than removing a marker from him. It falls on the eleventh or twelfth day, and the syllable is frequently taken from the lunar mansion under which the child was born, so that a horoscope becomes a source of identity as well as of prediction.
Jewish naming has an asymmetry that is now openly discussed. A boy is named at his circumcision on the eighth day, in a ceremony the whole community attends. A girl was traditionally named when her father was next called to the Torah, an event she need not be present for. The ceremonies of zeved habat and simchat bat, which put the daughter at the centre of her own naming, are twentieth-century creations, and they exist because the older arrangement came to be experienced as a statement about relative importance rather than a difference of convenience.
The widespread pattern of naming several days after birth rather than at it is usually explained by infant mortality: an interval let a household find out whether the child would live before conferring an identity on it. The traditions themselves almost never say this.