In John 17:3, Jesus defines eternal life as knowing God the Father and Jesus Christ. This word “know” is speaking of intimacy instead of mere intellectual knowledge; therefore, eternal life is having an intimate, personal relationship with God the Father and Jesus the Son.
According to John 3:16, this intimacy with God is what salvation is all about. Forgiveness of our sins is not the point of salvation — intimacy with the Father is. Of course, Jesus did die to purchase forgiveness for our sins because unforgiven sins blocked us from intimacy with God. Sin was an obstacle that stood between God and us. It had to be dealt with and it was. Anyone who views salvation as only forgiveness of sins, and stops there, is missing out on eternal life.
Forgiveness of sins is an essential step to relationship with God that cannot be bypassed, but it is not eternal life. Jesus didn’t die for us out of pity for our impending doom; He died for us out of love for us (John 3:16) — a love that longed to have that intimate communion with man that He had originally created him for (Gen. 3:8, Rev. 4:11).