This quote is taken from a sermon Charles Spurgeon preached on Psalm 90:17: Establish thou the work of our hands upon us; yea, the work of our hands establish thou it.
Do not have any fear of failure, beloved; if you really worked for God, you have worked for a cause that cannot know defeat. It may not win tomorrow, or the next day, but God can wait. Age comes upon us, but nothing shall ever make him decrepit; and through the course of ages, God can wait. I always feel, with regard to the causes in which we are engaged, when people tell us that we are in the minority, ‘Very well, we can be content to be in the minority at present, for the majority will be with us one day.’ We cannot doubt that when God is with us. Ay, and if we are alone with God, God makes majority enough for all true hearts. But even counting human heads, the truth shall yet have the majority. God can wait; he knows how to contrive gainsayers, and bring them round to his side. Our little plans come to an end in a few years; we cannot afford to bring them out unless they do; but God can let his capital lie idle for thousands of years if it is necessary. He is so rich that it does not impoverish him, and he will get his interest by-and-by.