The Quality of a Tree is Ascertained by its Fruits

“There is no ascertaining the quality of a tree but by its fruits. When the wheels of a clock move within, the hands on the dial will move without. When the heart of a man is sound in conversion, then the life will be fair in profession. When the conduit is walled in, how shall we judge of the spring but by the waters which run through the pipes?” (William Secker, quoted in Spurgeon, The Treasury of David, 1.181; cf. Psalm 15:2)