From a sermon by Alistair Begg on Christian living:
Now, in the divine order of things, God’s purpose is this: that our thinking was supposed to be informed and shaped and governed by his revelation. Okay? So that the way in which we think, in the purposes of God, was that we were supposed to “think God’s thoughts after him,” as it has been said. And it is when we think on the basis of God’s revelation—what he has made known of himself and of his purposes—that we then inform and we influence and we direct our powers of volition. So it is as I learn to think correctly that I then bring my doing into line with my right thinking.
That’s why we’ve got such a dreadful predicament in evangelicalism, because by and large evangelicals don’t think! It’s not a feature of evangelical Christianity, thinking. You talk to people about issues, they don’t know the issues. They only know the heroes. And then they line up behind the heroes: “What did Mr. X say about it? Oh, I like him. I think I probably believe what he believes. Oh, no, I like him a little better. I think I believe what he believes.” But they don’t think the issues out. And it is imperative that our thinking, then, constrains our doing. And that’s, you see, what transforms it all.
That’s why the hymn writer says, if I may pause for a moment, “’Tis what I know of thee, my Lord and God, that fills my heart with praise, my lips with song.”Now, this isn’t the same as saying, “I just want to praise you, lift my hands and say I love you.” Because as I’ve mentioned to you before, the circumstance of the hymn writer in the first instance may have been absolutely brutal. His job may have been lost, his marital existence may have been fractured, his children may have been a challenge to him. And if then he was going to allow the circumstances of his life to determine joy or sorrow, he has no chance in the world. So what then will grant to that individual stability? The answer is, “’Tis what I know of thee, my Lord and God, that fills my heart with praise, my lips with song.” In other words, it is his thinking that then determines his doing.