That said, there is hardly one of us who wouldn't benefit from calling ourselves to more rigor in our attitude toward truth.
Of course, it starts with attention to factual truth. You notice and make a point of calling yourself on the urge to conceal embarrassing facts, to try to make yourself look better, to justify mistakes, or run away from needed confrontation. When you notice the urge to tell an untruth, you check yourself. As much as possible, you make a point of not saying anything you know to be untrue.
As you learn to catch your own characteristic patterns of untruth—inner and outer—you will begin to notice that some truths need to be spoken, but that there are also times when remaining silent is an acceptable alternative to telling certain truths. In other words, your commitment to truthfulness comes to include an authentic, and trustworthy, capacity for discriminating speech.
Truth is a genuine teacher. When we make up our mind to follow where it leads, constantly asking ourselves questions like "What is my motive for speaking? Is it kind and necessary to say this? If not now, how will I know that it's right to say this?" the power of truth will show us its subtleties and teach us wisdom. Patanjali says that through truthfulness we gain such a power that all our words turn out to be true. I don't believe that he means that we become psychics, able to turn the base metal of lies into the gold of reality just by our words. Instead, I believe that he's talking about the power to speak from inspiration, to hold firmly to the truth that is not only factual, but that illuminates, that can be received, that reflects the deeper state of the heart.