Put simply, a sacrament is a created thing to which Jesus connected the forgiveness of sin. He did this with water and bread and wine. Traditionally these are known as baptism and the Lord’s Supper
But many Christians nowadays reject the idea of sacraments altogether. How is it that Jesus would do such a thing? To connect the forgiveness of sin to some created thing?
But of course Jesus Himself was a created thing. He is God who became man. And the cross upon which He died for the sins of mankind was also a created thing. And the words which He used to proclaim the Gospel were created things. And the ears that heard them were created things.
Why then water? As we all are born through water, and so it makes sense that we are reborn in baptism through the washing and regeneration and renewal of the Holy Spirit (Titus 3:5-8; Acts 2:38). As we daily are nourished physically by means of the earthly food we eat, it makes sense that we are nourished spiritually by the bread and wine of the Lord’s Supper, the body and blood of Christ, given and shed for us for the forgiveness of sin (Matt. 26:27-28).
Easy to understand? No. That is why they are called mysteries. Or in other words, sacraments.
So a better question may be on what basis water and bread and wine should be rejected by the modern Christian, and lights, and smoke, and loud music–also created things–should be embraced?
And then there is this: Jesus actually told his disciples to baptize “in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19) and said of the use of bread and wine: “Do this” (Luke 22:19).
Why? Perhaps it is because Jesus would come to us yet today as He came to mankind originally. That is, our Savior would come to us not in the loud and bright and overwhelming, but in the simple and humble and unassuming. That is in the water of baptism, and the bread and wine of the Lord’s Supper.