Jesus began his public ministry by being baptized in the Jordan River by John, who was his cousin and who "went before" Jesus as their tradition said that Elijah would "go before" the Messiah. This was a ritual cleansing, meant to forgive sins, and which allowing to have done to you meant that you repented of your sin. Hence, the Christian Church has established Baptism as a Sacrament--a holy moment.
Jesus ended his public ministry--before he was arrested and executed--by sharing in a meal with his disciples, at which he shared bread (which he broke, and said was his body) and wine (which he said was his blood--blood of the covenant, poured out for many). Hence, the Christian Church has established Holy Communion as a Sacrament--a holy moment.
Other branches of the Church recognize other Sacraments which we United Methodists don't put in that special category (marriage, confession, last rites, to name a few). We however, stick with these two.
And both are described by John Wesley (founder of Methodism) as "means of grace"--meaning that God is active and doing stuff that expresses love for us as they happen. Stuff that forgives us; stuff that "washes" us clean. Just as Jesus' own Baptism was a ritual washing, a washing away of sin and wrong, so we understand Baptism to do that. And just as the shed blood of Jesus forgives sin, so do we understand the sharing in the wine (for us, grape juice) in Communion to do that.
But it's not just a symbolic washing and forgiving that happens (although it is that, too). Both of these we understand as acts where God is present, where the Holy Spirit engages us (whether we sense it or not) and infuses us with God's grace and love. In Baptism (which we United Methodists understand as a one-time event, trusting God to never stop doing the work done at that time) we are forever freed by the Holy Spirit from the pentultimate power of sin to condemn us, since God's grace and love are ultimate, more powerful than sin. In Holy Communion, which we may share in frequently (John Wesley celebrated it every day, and a sermon he often preached was called "The Duty of Constant Communion"), the Holy Spirit consecrates the bread and wine (or in our case, grape juice) that it may be food for our journey of faith and life, and that we may be the presence of Christ in the world as we go out from worship.
So much more than this is going on in the Sacraments--whole books (some of which I've read!) have been written about each. But the key piece to remember at this time, is, as the sermon title affirms, "Christ is With Us in The Sacraments".
GOSPEL Mark 1:4-11
4 John the baptizer appeared in the wilderness, proclaiming a baptism of repentance for the forgiveness of sins. 5 And people from the whole Judean countryside and all the people of Jerusalem were going out to him, and were baptized by him in the river Jordan, confessing their sins. 6 Now John was clothed with camel’s hair, with a leather belt around his waist, and he ate locusts and wild honey. 7 He proclaimed, ‘The one who is more powerful than I is coming after me; I am not worthy to stoop down and untie the thong of his sandals. 8 I have baptized you with water; but he will baptize you with the Holy Spirit.’
9 In those days Jesus came from Nazareth of Galilee and was baptized by John in the Jordan. 10 And just as he was coming up out of the water, he saw the heavens torn apart and the Spirit descending like a dove on him. 11 And a voice came from heaven, ‘You are my Son, the Beloved; with you I am well pleased.’
GOSPEL Mark 14:12-16, 22-25
12 On the first day of Unleavened Bread, when the Passover lamb is sacrificed, his disciples said to him, ‘Where do you want us to go and make the preparations for you to eat the Passover?’ 13 So he sent two of his disciples, saying to them, ‘Go into the city, and a man carrying a jar of water will meet you; follow him, 14 and wherever he enters, say to the owner of the house, “The Teacher asks, Where is my guest room where I may eat the Passover with my disciples?” 15 He will show you a large room upstairs, furnished and ready. Make preparations for us there.’ 16 So the disciples set out and went to the city, and found everything as he had told them; and they prepared the Passover meal.
22 While they were eating, he took a loaf of bread, and after blessing it he broke it, gave it to them, and said, ‘Take; this is my body.’ 23 Then he took a cup, and after giving thanks he gave it to them, and all of them drank from it. 24 He said to them, ‘This is my blood of the covenant, which is poured out for many. 25 Truly I tell you, I will never again drink of the fruit of the vine until that day when I drink it new in the kingdom of God.’