Why would the Lord give to baptism—immersion in water—such an important role? The answer goes to the core of the Gospel. In 1 Corinthians 15, Paul summarizes the Gospel as an event: the death, burial and resurrection of Jesus.
Now I would remind you, brothers, of the Gospel I preached to you, which you received, in which you stand, and by which you are being saved, if you hold fast to the word I preached to you—unless you believed in vain. For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that He was buried, that He was raised on the third day in accordance with the Scriptures (1 Corinthians 15:1-4).
Twice, the Bible warns people to “obey the Gospel” (1 Thessalonians 1:8; 1 Peter 4:17). That raises the question, “How does one obey an event?” Jesus’ death, burial and resurrection are the main event of the Good News. We easily understand that one can hear and believe news. But how do you obey a news story?