"I came that they may have life and have it abundantly."
What is it to have life no less have life abundantly? Are we not alive? What exactly is Jesus doing?
It all may be simpler than you think. To be alive is to have life in you but life as we know it is ephemeral. It does not last. Though we are alive right now we may not be alive tomorrow. In that sense, we are barely alive, kept tethered to this world and animated only by a thin thread. Let's say the average lifespan is 80 years which is 5.81 x10^-9 (.00000000581) the age of the universe. Put another way, if the age of the universe was condensed to a year, one life span would take 0.18 seconds (180 milliseconds) to complete (about time it takes to do a Google search and half the time it takes to blink your eyes once (300-400 milliseconds). That's 5 generations per second with the human race appearing only in the last 12 and a half minutes.
So we are barely alive, containing only enough life to last a short while. But if we have eternal life in us, then we are eternally alive. And if that Eternal Life only exists in God, then only if God dwells within us can we live eternally. And if Jesus is God who truly did rise from the dead, he must possess eternal life. And if he dwells within us by faith, how much then will he have come so that we may have life and have it in abundance!