Isaiah 26:3 (ESV) … “You keep him in perfect peace whose mind is stayed on you, because he trusts in you.”
I. The promise. 1. It is universal in its range. It is made to any and every man who will trust in God. 2. It is sure. Men fail for various reasons to keep their promises, but every Divine promise is certain to be fulfilled (H. E. I. 4052, 4053). 3. The peace which is pledged and secured to all who will fulfil the condition of the text is perfect—so perfect that it can only be described by a repetition of the word, “peace, peace.” God never gives in driblets. His gifts are like Himself, perfect for their fulness, for their suitability, for their enduring qualities. God can keep His people in perfect peace when the devil accuses, when the world allures or threatens, when sickness tries, when adversity oppresses, even when the heart is sore tried, and when grim death would affright (H. E. I. 1253, 1893, 1894, 1911–1926; P. D. 2669, 2673).
II. The character described. “Whose mind is stayed on Thee, because he trusted in Thee.” Trust unites. The mind will not be stayed upon God unless there be perfect confidence in His wisdom, power, and love. Trust and love go together. Love begets confidence, and confidence strengthens love. The whole nature must be stayed on God, and on God only. There must be no division in the heart’s affections: we cannot serve God and Mammon and be kept in perfect peace. There must be trust before there can be peace; God Himself cannot give perfect peace to the untrustful.[1]
[1] Bertram, R. A., & Tucker, A. (1892). Isaiah 1–39 (Vol. 1, pp. 476–477). New York; London; Toronto: Funk & Wagnalls Company.