As for you, see that what you heard from the beginning remains in you. If it does, you also will remain in the Son and in the Father. And this is what he promised us - eternal life.
What have John's readers forgotten? What is it that has escaped by the back door, that has fallen away, that has been eroded by the lies of those who have come amongst them? John says that it is the first things. The simple things. The elementary truths (Hebrews 6.1). Our baby milk. (Hebrews 5.12)
We all too easily forget the basics, trying to munch our way through solids when actually our body is aching for the simplicity of milk. Desperate for fresh revelation, for new ways of knowing, for hearing what God has to say for today we sometimes neglect the beautiful things that he first said to us. We forget that day when he called us by name and said You are mine. (Isaiah 43.2) We fail to celebrate the wonders and the goodness of the good news.
And so, start at the very beginning (a very good place to start). Return to your first love. Remind yourself of the things you knew at first that have been neglected. You are loved. You are broken. You have been rescued. You are made for more than this. There is so much more than what the world has to offer (1 John 2.15-17). There is an eternity that awaits. Let's rejoice in that today.