He was a staunch defender of human rights, especially during the years of the Martial Law in the Philippines, being known to be one of the "Magnificent 7" who voiced their opposition to the Marcos regime.

[4] Labayen also served in various capacities in promotion of the welfare and rights of the poor and the marginalized, primarily in his appointment as the first chair of the Catholic Bishops' Conference of the Philippines (CBCP)'s National Secretariat for Social Action-Justice and Peace (NASSA).

The young man formally entered the Order of Discalced Carmelites on 15 October 1948 (Feast of Santa Teresa de Jesús) with the entrance to the novitiate in Brookline, Massachusetts.

[7] He was consecrated bishop on 8 September 1966 at the Carmelite church of Our Lady of Mount Carmel (now a national shrine and minor basilica) in New Manila, Quezon City.

The dexter side (left of the viewer) represents the Prelature of Infanta, according to the practice of combining the arms of the bishop with his territorial jurisdiction.

On the chief of the dexter (upper left) are symbols of the titular patrons of the prelature: the orb (Infant Jesus of Prague) and the lion (Mark the Evangelist).

On the base of the dexter (bottom left) is an azure background and fleur-de-lis representing the Blessed Virgin Mary and the three flowers symbolizing the Trinity.

His episcopal motto is "Dominus est" from the John 21:7 where the beloved disciple shouted "It is the Lord" and reflects a recognition of God in all circumstances of life.

[14] Long before the declaration of PCP-II, Labayen was an ardent proponent of the Church of the Poor in the Philippines[15] which was his brainchild in the Prelature of Infanta.