Isaiah 26: 3 (NIV)
You will keep in perfect peace those whose minds are steadfast, because they trust in you.
There are three elements to this verse. First perfect peace, second steadfastness and third trust. Perfect peace is the conclusion – that is where we want to arrive. We find that the way to that perfect peace is through steadfastness and trust.
So, what is steadfastness? The Tree of Life version reads, “You keep in perfect peace one whose mind is stayed on You.” People who keep their mind on God are kept in perfect peace. For some of us it would be enough to taste perfect peace every now and again but these people, those who keep their thoughts with God, abide in perfect peace. Honestly, though, it is no big surprise that perfect peace is in God. Jesus said that one of the things he left for us was his peace (John 14: 27). How can we not be in peace when we keep our thought lives enveloped in God? Jesus is the Prince of Peace. So, when we keep ourselves, our minds and our thoughts on God; when we are steadfast about what we let our minds meditate on then we will abide in that perfect peace.
Isaiah also revealed that keeping our mind stayed on God produces trust in Him and that trust leads to perfect peace. We might also speculate that the more we trust God, the more we do think about Him and about His way of perceiving things. Of course we experience more peace as our trust in Him increases. The more we keep our minds on Him and learn of Him, the more we trust Him. Then our peace increases.
So, it might be fair to say that in Him is perfect peace so that our only task, really is just to remain in Him. When we think about Him instead of thinking about the latest junk we heard on the news, then it is much easier to abide in peace. He is confidence and assurance. Think on Him instead of thinking on the things of the world and have joy and peace, perfect peace.