Baptism has been given a wide spectrum of meanings in Christendom as you well know. Theologians are experts at making things complex and more complicated than they need to be. The Scriptures are really fairly straight forward on the 
meaning and purpose of Baptism. “In keeping with the Jewish origins of baptism”, Fruchtenbaum says, “Baptism is an identification or association with a person or message or group.” When a gentile was converted to Judaism he was baptized. This is how he publicly announced his new association. Accordingly, John the Baptist baptized many followers and those who were baptized by him identified themselves with John’s message and committed themselves to accepting the Messiah. Identification with Jesus and His message is what believer’s baptism is all about. It’s a public identification with the death, burial and resurrection of Jesus, the Christ. Further, however, it is an identification with those in the past 2000+ years who have also identified with the death, burial and resurrection of Jesus; the Church. It’s an identification with the universal church, yes, but it is also an identification with the Church in the here and now.
Mark 16:16 is one of the troublesome verses. It says, “Whoever believes and is baptized will be saved…”Many have interpreted this as saying that both faith and water baptism are essential for salvation. Baptism is often used metaphorically in the Bible. If we can accept for just a moment that this verse is not talking about water we might grasp a different understanding. Think of it in terms of “identification.” If we’d interpret the metaphor it would say, ““He who believes in me and is identified with me shall be saved.” J. M. Boice argues that this perspective puts this verse in the “exact theological parallel to John 1:12 (“Yet to all who received him, to those who believed in his name, he gave the right to become children of God”) and Revelation 3:20 (“Here I am! I stand at the door and knock. If anyone hears my voice and opens the door, I will come in and eat with him, and he with me”). All three verses teach that there must be a personal identification with Jesus by the one believing.
In 1 Corinthians 10:1-2, Paul says, “I want you to know, brethren that our fathers were all under the cloud, and all passed through the sea, and all were baptized into Moses in the cloud and in the sea.” Boice rightly argues, “That passage is especially significant in understanding baptism, since the people of Israel were obviously not immersed either in the sea or the cloud. The cloud was behind them, separating them from the pursuing Egyptians. The Egyptians were immersed in the sea, and they drowned in it. The meaning here is a change of identity. Before the crossing of the Red Sea the people were in rebellion against Moses. Their original attitude changed into an attitude of obedience and rejoicing after the Red Sea crossing.”