That there is only one God, and that he has revealed himself to mankind through the things that he has made, his written word (the Bible), and through his only son – Jesus.
That God made mankind to glorify Him and enjoy Him forever; but that mankind has rebelled against God and has therefore become alienated from Him.
That God has done something to resolve this problem and reconcile people to Himself.
That God’s solution to man’s problem is His Son Jesus, who (on our behalf) lived the perfect life of obedience that we could not live; and who (on our behalf) suffered the terrible penalty that we deserved – on the cross.
That God now ‘freely’ offers forgiveness to those who will ‘freely’ accept it … as a gift!
That this gift is given to those who will ‘repent’ (ie. turn to God) … and ‘believe’ (ie. trust in what Jesus has done for them, and acknowledge him as Lord of their life).
That Jesus has been raised from the dead – and is alive!
That he has been rewarded by God with power and authority over everyone, and everything!
And that, in accordance with the Bible, Jesus will return. And at that time, God’s great plan for his creation will be fulfilled: Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away … And I heard a loud voice from the throne saying, “Now the dwelling place of God is with men, and he will live with them. They will be his people, and God himself will be with them and be their God … [and] he who was seated on the throne said, “I am making everything new!” [Revelation 21:1-5]
A more detailed expression of what we believe can be found in the Westminster Confession of Faith.