Baptism is the first of the great Journey Sacraments.
Water is a major theme in the Bible, from Creation as the Spirit of God brooded over the water there are many images of water. Abraham traveled from the land of the great rivers (Tigris & Euphrates) to a well on the Hill at Shiloh. Moses led the Hebrew People across the Red Sea as on dry land, and when they were thirsty he struck the rock with his staff and water came forth. David the Psalmist spoke of being led by still waters. John came Baptizing in the River Jordan. Jesus took water at the wedding and made it wine. Jesus said to Nicodemus said we must be born of water and Spirit, and met the woman at the well that Abraham had traveled to in a narrative that concludes with him being called the Savior of the World. When Jesus was crucified water came forth from his side mingled with blood. In the great vision of heaven in the last book of the Bible the great river flows from the Throne of God.
By the sacrament of Holy Baptism we come into the Church. The Font in that sense is the door of the Church. In this sacrament we are made one with Christ (hence it sometimes being called Christening). The journey of faith does not end in Baptism, it begins here. Parents and Godparents promise to nurture the journey.