It was hard enough for early Christians after most of the apostles died. Less than 40 years after Jesus' ascension, Jerusalem was leveled and the temple was destroyed. John writes to these persecuted Christians of the things to come.
You are not primarily a body. You are not primarily a soul. You are a person with both body and soul. Both are essential components of the human person.
What do we do when things are out of our control, when we face opposition from without or from within? We hope in Christ and rest in the promises of God.
We are saved and become Christians by believing in the atoning death and resurrection of Jesus. However, in order to grow and become mature as Christians we must abide in Him.
Is Jesus the basis for your being made right before God, or is He not? Do you simply have to believe, or are there certain things you have to do to be saved?