The Gospel is the Good News of the Father sending His Son (Matthew 3:17, 17:15, Mark 1:11) Jesus Christ (I John 4:2-3, 4:15, 5:1) into the world to save sinners (I John 3:5, 4:14) from His wrath so the sinner would by faith in the person and work of the Son receive forgiveness and covering of their sins in order to be reconciled to the Father (2 Cor 5:18-19) and have everlasting life with Him.
This wrath abides upon each individual sinner which at the sinners physical death will come upon them forever (John 3:36; Eph 2:3, 5:6; Col 3:6; I Thess 1:10, 2:15-16, ). Every soul is born into this world with a sin nature (Psalm 51:5) and is thereby alienated from God all of their life until or unless they repent of their unbelief and turn to the Lord Jesus Christ for the forgiveness of their sins and reconciliation with the Father.
Thus the Father, in the fullness of time (Galatians 4:4), sent His only begotten Son, Jesus Christ, into the world to accomplish salvation for repentant souls (Titus 3:4-7). Through all aspects of His life, death, resurrection and ascension Jesus accomplished all aspects necessary for repentant sinners salvation (Romans 3:2; Hebrews 2:17; 1 John 2:2; 1 John 4:10). Therefore through faith alone (Romans 1:17; Galatians 3:11) in Jesus Christ alone (John 8:24; Hebrews 5:9, 7:28, 9:11-15, 9:24-26, 10:9-18; I John 4:9, 5:11-12; Titus 2:11-14) is a repentant sinful soul reconciled ( II Cor 5:18-19) to the living God.
Upon calling upon the Name of the Lord (Romans 10:9-10) for the forgiveness of their sins the soul is declared righteous (the just life by faith), receives the Holy Spirit (Acts 2:38) as an ernest deposit of their expressed faith, enters the Kingdom of God (Heb 12:22-24), lives a life of following Christ’s teaching (this is called sanctification Hebrews 2:11; Titus 2:14; I John 5:3) and when the sinner who is now called a Saint dies the Holy Spirit will raise them from the dead into the Father’s presence (this is called glorification).
The purpose of this great salvation, which is called eternal life, is that souls would come to know their creator, the true and living God and worship and enjoy Him forever.
Jesus sums this up in John 17:3, “This is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent.”