The gospel is the good news that the kingdom of God has come near in Jesus Christ. And that through his life, death, resurrection, and enthronement, the powers of sin and death no longer have the last word.
The Word of God calls us to a new life as disciples of Jesus in the kingdom of God by repentance toward God and faith toward Jesus Christ.
Repentance is turning from sin and all ways of trying to please God through good works.
Faith is trusting in the finished work of Christ on the cross for salvation.
"That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.
For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation." -Romans 10:9,10