During a hip-opening posture in yoga, my instructor tells me, “Make sure the tension from your hips is not going anywhere else in your body. Wherever you are feeling tension, let it go.” With my eyes closed, I think of this. I realize that my eyebrows are creased with concentration, so I let the tension go, relaxing my face. Next, I focus on the tension in my legs. I ask myself, should I let this tension go? But I cannot, at least not completely, without falling out of the pose. Some tension is necessary to maintain the pose. In this moment I learn again, from my body, something that I have learned before: there is a balance, between focused effort on what is essential, and letting go of what is not.