Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee. Isaiah 26:3.
What is perfect peace? It is a peace that passes all understanding (Phil. 4:7). It is the peace of God (Phil. 4:7; Col. 3:15). It is peace with God (Rom. 5:1).
There is no peace in the earth except that peace which rests in the hearts of believers in God and his Son, Jesus Christ. This peace resides deep in the recesses of the inner being of the believer. It is difficult to understand and to explain. Like the calm which Jesus manifested as he slept on the boat in the midst of a vehement storm (Matt. 8:24), like the calm on the sea just after the Lord said "Peace, be still" (Mark 4:39), we can have this same peace in our hearts, though the world give us grief, trouble, and sorrow.
There is no break in perfection: it is constant and continuous. This perfect peace rises above our trials and our worries. It settles arguments and brings friendships. It edifies saints and enhances fellowship among believers. That is because it is God's peace. There is a song that says so correctly, "There's a deep settled peace in my soul."
If you do not have that spiritual peace with God, you can through faith in Jesus Christ, his Son, believing that he died to pay for sin, that he was buried and rose again the third day according to the scriptures. Bring your heart and soul into that permanent peace with God through justification by faith (Romans 5:1).