“The time has come,” he said. “The kingdom of God has come near. Repent and believe the good news!” – Mark 1:15 (NIV)
Repentance and belief are what lead to salvation. The first calling for us as believers is to salvation. We are called to believe the Good News (the gospel). Upon our internal belief in it, then we confess our belief in Jesus as Savior before men. This our public profession of Him as our personal Savior.
This is our first calling as Christian. It is what makes us Christians. We accept Christ as Savior and enter an entirely different realm of existence, for His Spirit indwells within us upon belief. That is the baptism of the Holy Spirit.
Many of us may differ upon the numerous other things that transpire upon belief. Some things are more inherent to our denominational traditions and beliefs rather than biblical facts. However, as believers, we all have a common faith with Christ as the head authority over us all.