Nothing can be lasting that is not built on God alone. How can you have settled peace? You can only have it in God's way, by not resting on anything, even the Spirit's work, within yourselves, but on what Christ has done entirely without you. Then you will know peace. You will be conscious of your own unworthiness, but full of peace.
In Christ alone, God finds that in which He can rest, and so it is with believers. The more you see the extent of the evil that is within, as well as that without and around, the more you will find that what Jesus is, and what Jesus did, is the only ground at all on which you can rest.