Charles H. Spurgeon on Psalms 23:1

"The Lord is my shepherd." We may learn in general from the metaphor, that it is the property of a gracious heart to draw some spiritual use or other from his former condition. David himself having sometimes been a shepherd, as himself confesseth when he saith, "he took David from the sheepfold from following the sheep," etc., himself having been a shepherd, he beholds the Lord the same to him. Whatsoever David was to his flock — watchful over them, careful to defend them from the lion and the bear, and whatsoever thing else might annoy them, careful of their pasturage and watering, etc., the same and much more he beholds the Lord to himself. So Paul: "I was a persecutor, and an oppressor: but the Lord had mercy on me." This we may see in good old Jacob: "With this staff," saith he, "I passed over Jordan;" and that now God had blessed him and multiplied him exceedingly. The doctrine is plain; the reasons are, first, because true grace makes no object amiss to gather some gracious instruction: it skills not what the object be, so that the heart be gracious; for that never wants matter to work upon. And secondly, it must needs be so, for such are guided by God's Spirit, and therefore are directed to a spiritual use of all things. Samuel Smith's "Chiefe Shepheard," 1625.