A mature oak displays its strength and longevity.
Here, in John 14, Jesus speaks to the disciples in the upper room about leaving them with a lasting and new quality of peace. A God-quality of peace. This information was given just shortly before His own self-sacrificing death for our sins, burial, and resurrection.
John 14:27 Darby Translation (DARBY)
27 “I leave peace with you; I give *my* peace to you: not as the world gives do I give to you. Let not your heart be troubled, neither let it fear.”
Jesus left Christians (“in Christ ones”) with a kind of peace that remains. His type of peace gives the ability to have a heart (center of reasoning) that is neither troubled nor fearful. The peace from God is distinctly different than the world’s type of peace. God’s peace is not dependent on smooth circumstances, negotiated alliances, or cease-fires.