Jesus died during a darkening of the sun (Mk 15:33). Jesus died when midafternoon seemed like midnight. He died because of the night of our sins which the prince of darkness (see Eph 6:12) used to crucify the Light of the world (see Jn 8:12). When we betray, deny, ignore, or disobey Jesus, we turn out our light and enter into the night (Jn 3:19ff). However, when we repent, give ourselves totally to Jesus, and live our Baptisms, we too are the light of the world (Mt 5:14). Even we, who were darkness, are now light in the Lord (Eph 5:8).
In four days, at Easter Vigil, after it is dark, we will enter a dark church led by the light of the Paschal candle. Because this light pierces the darkness of sin, death, and Satan, at Easter Vigil we will proclaim the light of Christ and exult in thanksgiving for Jesus, the Light of life (Jn 8:12). For those in Christ, "the Light shines on in darkness, a darkness that did not overcome It" (Jn 1:5). "The night shall be no more" (Rv 22:5).