CCC 694 Water. The symbolism of water signifies the Holy Spirit’s action in Baptism, since after the invocation of the Holy Spirit it becomes the efficacious sacramental sign of new birth: just as the gestation of our first birth took place in water, so the water of Baptism truly signifies that our birth into the divine life is given to us in the Holy Spirit. As “by one Spirit we were all baptized,” so we are also “made to drink of one Spirit.”1 Thus the Spirit is also personally the living water welling up from Christ crucified2 as its source and welling up in us to eternal life.3
1 1 Cor 12:13.
2 Jn 19:34; 1 Jn 5:8.
3 Cf. Jn 4:10-14; 738; Ex 17:1-6; Isa 55:1; Zech 14:8; 1 Cor 10:4; Rev 21:6; 22:17.