Did you know that Easter is not just a day, but also a season?  The Easter Season fulfills two functions in the Church's observance of Christ's resurrection from the grave; 1. It allows us to see what caused the early community of Jesus' Way to believe that Jesus had been resurrected, and 2. It leads us to the Day of Pentecost, when the Holy Spirit descended to empower the early disciples to take the Word to all nations. 

To fulfill the first function of teaching us about Jesus' post-resurrection ministry, we hear the stories of Jesus showing up to disciples and the wider community (12 of these are recorded in New Testament accounts).  But, we are also informed in John 20 that, "Jesus did many other signs in the presence of his disciples, which are not written in this book. But these are written so that you may come to believe that Jesus is the Messiah, the Son of God, and that through believing you may have life in his name."  So, we witness both the fact of Jesus' resurrection as recorded by multiple sources, and we see the purpose, which is to empower and embolden us to believe that God will raise us with Christ on the last day.

The second function of the Easter Season is to mark the 49 days between Easter Day and the Day of Pentecost (The word "Pentecost" is simply the Greek word "fiftieth" for the fiftieth day after Easter).  This Christian season is directly related to the 49 days between the Jewish holidays of Passover and Shavuot, which is the season that celebrates the Hebrew people being freed from slavery in Egypt and the weeks (Shavuot means "weeks" in Hebrew) that it took to get to Sinai for the revelation of the Ten Commandments.  And so we can see, from a Christian perspective, that our Passover (when Jesus's sacrifice released us from slavery to Sin) leads us on a journey through the Easter Season toward Pentecost (the day that we celebrate our Sinai-like revelation of the Holy Spirit).