Charles H. Spurgeon on Psalms 119:80

Let my heart be sound. "A sound mind in a sound body, " was the prayer of a heathen, and his desire was according to the extent of his knowledge; but a heart sound in God's statutes, sound to the very core, with no speck, nor spot, nor wrinkle, nor any such thing, and like the king's daughter, "all glorious within." this is what the Psalmist prays for, this is what every child of God aims at, and prays for too, "Even as He is pure." Barton Bouchier.