One tree is covered in leaves & teeming with fruit; the other, well, it's surrounded by desert & there is not one leaf on it.
Now, which of these trees would you say is without doubt alive?
Of course all of us are going to point to the tree with leaves & fruit, after all it's flourishing!
But as we point to the leaves & fruit let's ask; 'do the leaves & fruit make the tree alive or give it life?'
No, of course not, rather the leaves & fruit exist because the tree is alive, also serving as signs of the trees health.
This is a great illustration as to the Christian, their life & good works!
Good works & Christian activity, (reading our Bibles, praying, fasting etc) do not make us alive in Christ; they do not save us or win favour with God. Rather they are a result of having been born again & of the Life, forgiveness, favour & merit with God that they already have because of Jesus Christ's life, death & resurrection.
Some Scripture to consider
For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast. For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.
All our righteousness is like filthy rags.