"The fruit of the righteous is a tree of life; and he that winneth souls is wise." (Proverbs 11: 30)
In the beginning, God intended for man to partake from the tree of life:
"And out of the ground made the LORD God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of knowledge of good and evil." (Genesis 2: 9)
God places the tree of life in the middle of the garden, giving that tree its due prominence.
Yet Adam and Eve ate from the tree which was good, but not for man, and thus they died spiritually and were destined to die physically.
They could not eat from the tree of life at that point:
"And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:" (Genesis 3: 22)
It was God's love which sent the first man and woman out of the Garden. Imagine living in sin and death forever, without any change. Such misery God never intended for us.
So, the tree of life is a picture of our Lord Jesus.
He is referenced as such later in the Scriptures:
"She is a tree of life to them that lay hold upon her: and happy is every one that retaineth her." (Proverbs 3: 18)
While the verse refers to Wisdom, the truth is that through the New Covenant, Christ Jesus is made Wisdom for us, and then our righteousness. (1 Corinthians 1: 30)
We are blessed and become the righteousness of God in Christ, because He became sin for us (2 Corinthians 5: 21)
God prophesies about the new birth through Christ in reference to trees coming to life:
"And all the trees of the field shall know that I the LORD have brought down the high tree, have exalted the low tree, have dried up the green tree, and have made the dry tree to flourish: I the LORD have spoken and have done it." (Ezekiel 17: 24)
When we receive Jesus as our life, we can partake of the tree of life freely in heaven, too:
"Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city." (Revelation 22: 14)
Partake of Jesus, grow in grace and knowledge of Him, and because of His righteousness, you have life, His!