Now that is obvious in any one of the Epistles, and it is equally obvious here. Take any Epistles you like. You will find that the subdivision in each one of them is the same; always doctrine first, then deductions from doctrine. The great principles are laid down and a description is given of the Christians to whom the letter is written. Then, because of that, or because they believe that, ‘therefore’ they are exhorted to do certain things.
D. Martin Lloyd-Jones, Studies in the Sermon on the Mount, P. 17