'Tree of Life' in the Bible

He that has an ear, let him hear what the Spirit says to the assemblies. To him that overcomes, I will give to him to eat of the tree of life which is in the paradise of God.

In the midst of its street, and of the river, on this side and on that side, the tree of life, producing twelve fruits, in each month yielding its fruit; and the leaves of the tree for healing of the nations.

Blessed are they that wash their robes, that they may have right to the tree of life, and that they should go in by the gates into the city.

And if any one take from the words of the book of this prophecy, God shall take away his part from the tree of life, and out of the holy city, which are written in this book.