Certain special times and events in the course of life present themselves as occasions that are set apart and celebrated, because they direct human thought to the divine and the sacred with peculiar forcefulness. These occasions, called life crises, are regarded as dangerous because they are transitional from one stage of life to another and open to view the relation of life as a whole to its sacred ground.
Pregnancy and birth, the naming of a child, being initiated into the community – sometimes called “puberty rites” – the choice of a vocation, the celebration of marriage, and the time of death are experienced as special events distinct from the routine happenings of secular life. These events represent “crises” – i.e., turning points – when the human relation to the sacred becomes a matter of special concern (see also rite of passage).
As Gerardus van der Leeuw, a Dutch phenomenologist and historian of religions, points out, these transitional times are occasions for celebration in every culture because they mark the death of one stage and the birth of another in a universal cycle of life.
From Encyclopedia Britannica
Religious Experience: Life crises and rites of passage