Joy, bliss and rapture can produce tranquility. We can associate being peaceful with tranquility. Focusing on tranquility and a more spacious and silent perspective in the face of difficult raptures can help you ride them out, and just sitting silently and observing reality do its thing can be very powerful practice. There are actually whole schools of spiritual practice dedicated to this. Thus, tranquility is a really good thing in meditation. We may think of great spiritual masters being internally tranquil, and while it may or may not be true, there are reasons why we associate tranquility with spirituality. A mind that is not tranquil will have a harder time concentrating and being balanced. It is just as simple as that. Being kind and moral can help with tranquility, as this lessens the harsh thought patterns in our minds.
This does not mean that non-tranquil moments are not “spiritual” or that we must adopt some sort of restrained and artificial flatness. Remember, all types of sensations, mind states and actions are valid phenomena for investigation and real expressions of what is going on. Real tranquility comes from a deep understanding of all of this, but all too often this ideal becomes some sort of dehumanizing exercise in passivity. Real tranquility often comes naturally, though it may be skillfully cultivated as well. Cultivating equanimity of the kind mentioned later is helpful for cultivating tranquility, as is deepening in pure concentration practices, the second spiritual training. Tranquility, concentration and equanimity are intimately related.