There is one God, who has revealed Himself as Father; through His Son, in redemption; and as the Holy Spirit, by emanation. Jesus Christ is God manifested in flesh. He is both God and man.
Hear, O Israel: The Lord our God is one Lord:
There is one body, and one Spirit, even as ye are called in one hope of your calling; One Lord, one faith, one baptism, One God and Father of all, who is above all, and through all, and in you all.
For in him dwelleth all the fulness of the Godhead bodily.
I Timothy 3:16
And without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the Spirit, seen of angels, preached unto the Gentiles, believed on in the world, received up into glory.
The saving gospel is the good news that Jesus died for our sins, was buried, and rose again. We obey the gospel by repentance (death to sin), water baptism in the name of Jesus Christ (burial), and the baptism of the Holy Spirit with the initial sign of speaking in tongues as the Spirit gives the utterance (resurrection).
II Thessalonians 1:8
In flaming fire taking vengeance on them that know not God, and that obey not the gospel of our Lord Jesus Christ:
I Peter 4:17
For the time is come that judgment must begin at the house of God: and if it first begin at us, what shall the end be of them that obey not the gospel of God?
I Corinthians 15:1-4
Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures:
And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.
Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do? Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call.
Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death? Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
Jesus Christ is coming again to catch away His church. In the end will be the final resurrection and the final judgment. The righteous will inherit eternal life, and the unrighteous eternal death.
I Thessalonians 4:16-17
For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them. And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works. And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works. And death and hell were cast into the lake of fire. This is the second death. And whosoever was not found written in the book of life was cast into the lake of fire.