By do not be anxious about anything, but in everything by prayer and supplication with thanksgiving let your requests be made known to God. And the peace of God, which surpasses all understanding, will guard your hearts and your minds in Christ Jesus. (Philippians 4:6–7 ESV)
Peace is not only the absence of conflict, but also the positive blessing of being in a right covenantal relationship with God through Christ. When this relationship is real and not imaginary, the peace of God surpasses human understanding and acts as a guard around our heart and mind. This guarded peace is perfect, and can be sustained when the person who is guarded keeps their mind stayed on the Lord (Isaiah 26:3), the trustworthy King. Therefore, we are not to be anxious about anything. And every request we have is to be brought before our King through prayer and supplication.
I think one of the keys to this peace is in that powerful word thanksgiving. We are always to be a thankful people. Not a superficial, smiley denial of conflict or pain; but rather a prayerful trusting upon the sovereign Lord who is for me and not against me. It was displayed for me in perfection last week through my beloved wife when she said after the death of our daughter Mercy; “I have never been so broken and thankful in all of my life.” This is a true child of the King who is being kept in perfect peace in the midst of conflict, anguish, and pain. This is a woman who is in a right covenantal relationship with God through Christ. She has the peace of Christ that surpasses all understanding.
You keep him in perfect peace whose mind is stayed on you, because he trusts in you. (Isaiah 26:3 ESV)
Leading Family Devotions 
Thank you for your insight. Being broken and thankful shouldn’t go together, but the peace that surpasses all understanding is just that, not understandable unless you have that right relationship with God, which truly comes from being thankful for all things, not just good things in our eyes but all things, because all thing are working together for our good.
Praying for your family.
Thanks for your encouragement and your prayers.
I love that verse (Isaiah 26:3) and was just thinking about it this morning. Thank you for your thoughts, and for giving me better ways to pray!
I had let the cares of the day overwhelm me and cause me to fall into the woe is me, self pity mode. I quickly turned my thoughts to your family and your suffering at the loss of your child. I remembered an article I had read a few years ago by Dr. Ed Welch, titled “No more minimizing pain” With God there is no suffering gauge, no compassion meter. He never compares our suffering to anyone else’s. He constantly invites us to call out to Him! How blessed our we that He cares about every aspect of our life, big or small. Psalm 130: 1 Out of the depths I have cried to you O Lord, Lord hear my voice! Let your ears be attentive to the voice of my supplications. Again, thank you for sharing this part of your life with us, it is causing me to ponder the goodness our Lord.