If sin is a disease of human nature, then salvation is the healing of our sin-diseased nature . Sinners not only need pardon, but also power that would transform them inside and out. They need healing, transformation, cleansing, change of heart and mind. The Western and Eastern branches of the early church also viewed the sacraments differently. When one is baptized God has placed His seal of approval on that individual.
Baptism takes away the guilt of original sin.
That is why infants are baptized. Likewise, to receive the Eucharist one must first be properly certified. When one receives the Eucharist, the seal of approval remains in force. There were a lot of debates as to who may receive communion and who may not. Likewise, there were debates as to who is qualified to bestow it or administer it and who is not.