Do good, O LORD, unto those that be good. They consult their own good best, who do most good. I may say these three things of those who do good (and what is serving God but doing of good? or what is doing good but serving God?). First, they shall receive true good. Secondly, they shall forever hold the best good, the chief good; they shall not only spend their days and years in good; but when their days and years are spent, they shall have good, and a greater good than any they had, in spending the days and years of this life. They shall have good in death, they shall come to a fuller enjoyment of God, the chief good, when they have left and let fall the possession of all earthly goods. Thirdly, they that do good shall find all things working together for their good; if they have a loss they shall receive good by it; if they bear a cross, that cross shall bear good to them.—
Joseph Caryl, 1602-1673, quoted in Charles Spurgeon's The Treasury of David, on Psalm 125, verse 4.