Charles H. Spurgeon on Psalms 116:6

The simple. They are such as honestly keep the plain way of God's commandments, without those slights, or creeks of carnal policy, for which men are m the world esteemed wise; see Ge 25:27, where Jacob is called a plain man. Simple or foolish he calls them, because they are generally so esteemed amongst the wise of the world; not that they are so silly as they are esteemed; for if the Lord can judge of wisdom or folly, the only fool is the Atheist and profane person (Ps 14:1); the only wise man in the world is the plain, downright Christian (De 4:6), who keeps himself precisely in all states to that plain, honest course the Lord hath prescribed him. To such simple ones, God's fools, who in their misery and affliction keep them only to the means of deliverance and comfort which the Lord hath prescribed them, belongs this blessing of preservation from mischief, or destruction: so Solomon (Pr 16:17), "The highway of the upright is to depart from evil." "He that keepeth his way preserveth his soul"; see also Pr 19:16,23; for exemplification see in Asa, 2Ch 14:9-12 16:7-9, read the excellent speech of Hanani the seer. William Slater, 1638.