Following the Gospel of John, we continue into the other "Johannine" books (works written by the apostle John). We can easily find many similarities between John's Gospel and his first letter known as I John.
John begins, again, with an emphasis on Christ as the Word who existed from the very beginning. This matches the way he began his gospel. In terms of vocabulary, John continues to employ very stark nouns to describe profound spiritual concepts: Life, Light, Darkness, Truth, etc. John consistently maintains his status as an eyewitness sharing his testimony.
In the opening verses, we see John emphasize both the spiritual aspect of Jesus as the Son of God, as well as His physical manifestation in the flesh, able to be seen and handled. As the early Christians struggled to comprehend Jesus, the biblical authors keep them from making two mistakes: to believe that Jesus was merely a man, nothing more; and to assume that He was purely divine and His appearance on earth was only a mirage. John, and the other apostles, were adamant that Jesus is both the very Son of God (really!) Who was manifest in the flesh, lived, suffered and died (really!) as a human being.
Do you tend to focus more on Jesus' humanity or His divinity?