Christians who are lacking God's peace have not taken their cares to the Lord and left them there. All Christians have peace. It is a fruit of the Spirit that is always present in our born-again spirits. Cares will blind us to God's peace. When we eliminate the cares, peace comes.
Being carnally [naturally] minded is death. Being spiritually minded is life and peace. A person who says he or she is spiritually minded and yet is experiencing death is deceived. If we would just dominate ourselves with the spiritual truths of God's Word, we would receive only life and peace.
True peace, which comes from God, only comes by grace through faith. No one who seeks to obtain right standing with God by his own effort will ever have God's peace.
Human peace is only experienced in the absence of problems. Those who only know human peace don't experience it very often and to a lesser degree. But God's peace is independent of circumstances and infinitely greater in supply than any problem we could ever have. God has given us His supernatural peace to enjoy. What a blessing!