The purpose John wrote this epistle was to give assurance of eternal life to those who believe in Jesus as the Christ. He wanted to confirm our relationship with God, Jesus, The Holy Spirit, and with one another. There were times when people were not sure about Jesus, but John gave readers then and now the test of actually knowing Him. He also exposed the world for what it is and warned us from loving the things in the world and the deceptions in these last days. John urges us to allow the Holy Spirit to abide in us because the Holy Spirit is Truth and when we allow this, we are actually walking in victory.John talked about knowing the spirit of error and knowing the truth which is vital for today's Christian. The only way to know the Spirit of error is to have our belief system grounded in the Truth.