Colossians 3:15

And let the peace of God rule in your hearts, to which also you were called in one body; and be thankful.

What does strife do to us?  It causes anger, turmoil, sadness, depression and cuts off the inflow from God.  Peace allows the goodness of God to flow through us and helps us keep the flesh under control.  Our hearts when ruled by God’s peace has the assurance that it can overcome any circumstance.  Fear doesn’t have that.