Article: Sacerdotalis caelibatus (Latin for "Of the celibate priesthood"), promulgated on 24 June 1967, defends the Catholic Church's tradition of priestly celibacy in the West. This encyclical was written in the wake of Vatican II, when the Catholic Church was questioning and revising many long-held practices. Priestly celibacy is considered a discipline rather than dogma, and some had expected that it might be relaxed. In response to these questions, the Pope reaffirms the discipline as a long-held practice with special importance in the Catholic Church. The encyclical Sacerdotalis caelibatus from 24 June 1967, confirms the traditional Church teaching, that celibacy is an ideal state and continues to be mandatory for Roman Catholic priests. Celibacy symbolizes the reality of the kingdom of God amid modern society. The priestly celibacy is closely linked to the sacramental priesthood. However, during his pontificate Paul VI was considered generous in permitting bishops to grant laicization of priests who wanted to leave the sacerdotal state, a position which was drastically reversed by John Paul II in 1980 and cemented in the 1983 Canon Law that only the pope can in exceptional circumstances grant laicization.

Now answer this question: What is seen as symbolizing the reality of living in the modern world as Roman Catholic priest?
Celibacy