She delighted in seeing her plan upset by unexpected events, saying that it gave her great comfort, and that she looked on such things as an assurance that God was watching over her stewardship, was securing the accomplishment of His will, and working out His own designs. Whether she traced the secondary causes to the prayer of a child, to the imperfection of an individual, to obstacles arising from misunderstandings, or to interference of outside agencies, she was joyfully and graciously ready to recognize the indication of God's ruling hand, and to allow herself to be guided by it
--from The Life and Letters of Janet Erskine Stuart
To me a quiet and gentle spirit is just that kind of peace.
Having a quiet spirit, no matter what comes your way, and believing that you are still being taken care of by your loving, Heavenly Father.
I am certainly not at the point where I am delighted at seeing my plans upset, but I do fret less than I did when I was younger. So I guess I am headed in the right direction.
"I lift up my eyes to the hills - where does my help come from? My help comes from the Lord, the Maker of heaven and earth. He will not let your foot slip - he who watches over you will not slumber; indeed, he who watches over Israel will neither slumber nor sleep. The Lord watches over you - the Lord is your shad at your right hand; the sun will not harm you by day, nor the moon by night. The Lord will keep you from all harm - he will watch over your life; the Lord will watch over your coming and going both now and forevermore."