Some people are confused about the name "Good" in Good Friday, because the name seems out of place when remembering an execution. The name is probably a corruption of the name, "God's Friday", but in another sense, "good" is appropriate too, since Jesus' death was ultimately for our good.
Peter preached to the crowd on the Day of Pentecost to explain what had happened when Jesus was crucified. He explained that Jesus was accredited by God by miracles, wonders, and signs to show that Jesus was the Messiah, who was promised to the Jewish nation through the prophets. Peter added that Jesus was handed over to them by God's set purpose and foreknowledge (see Isaiah 53:10).
Why would God sacrifice His only begotton Son? Jesus did nothing to deserve death. He was sinless and yet he died for our sins. Scripture tells us in John 3:16 that God loved the world so much that he gave his Son (as a sin offering) so that whoever believes in Jesus (believes and trusts in Jesus, that his death and resurrection paid our debt of sin to God) will have everlasting life.
Peter went on to say that everyone in the crowd should repent and be baptized, in the name of Jesus Christ for the forgiveness of their sins and they would receive the gift of the Holy Spirit. "The promise is for you and your children and for all who are far off - for all whom the Lord our God will call."
Here at Bethlehem and St. John Ev. Lutheran Church, we remember Jesus suffering and death on Good Friday. The services are dark and sober, highlighting the shame of our sin and the lengths to which Jesus went to save us. The darkness of the Good Friday service serves to heighten the joy by the contrast of Easter, a worship service filled with light and joy. Joy that he who once was dead is risen. "He is risen indeed!"