Obedience is not eternal life. It may be an evidence that we have eternal life. But it is no guarantee. Those in
Matthew 7:21-23
Eternal life is not obedience. Eternal life is knowing God and Christ. The passage you site merely states that obedience may be evidence that one possesses eternal life. It is one of five tests that the Apostle John reveals in the epistle. If one is meeting all the conditions stipulated, chances are good that they possess eternal life.
Knowing God and Christ is altogether different. This requires actual interaction and experience of God. Let's look at some examples:
...Romans 8:16 says the Spirit of God witnesses to our spirits that we are the children of God. Have you experienced this?
...Matthew 6:6 says we are to pray in secret and our Father who is in secret will meet us there. Have you experienced this?
...Hebrews 4:16 says we can come boldly to the throne of grace that we may obtain mercy and find grace to help in time of need. Have you experienced this?
...on the road to Emmaus Jesus opened the understanding of His fellow travelers. Have you ever experienced this?
Again, eternal life is not obedience, but may be evidenced by obedience. Eternal life is actually engaging with God through the life of Christ in us.