The well-known opening verse from the Buddhist text The Dhammapada:
Mind is the forerunner of all things
Act and speak with an unwholesome mind,
And unhappiness will follow you
As surely as the wheel of the cart follows the ox which draws it.
Mind is the forerunner of all things.
Act and speak with a wholesome mind,
And happiness will follow you
Like your never departing shadow.
Sounds like a simple and clear instruction. But what is wholesome vs. unwholesome mind? Wholesome mind refers to wise, kind states of mind like compassion, joy, equanimity, generosity and love. These mind states originate from wisdom and an understanding of the truth of interconnection. Unwholesome mind refers to states that originate in delusion and a sense of separation, such as aversion, greed, fear, hatred, jealousy, revenge or confusion. They are suffering in the moment they have arisen, and the speech and actions taken from these states have unpleasant results for oneself and others.
During the course of one day, we can have a wide variety of mind states appearing, like different colored lenses that drop in front of our eyes. Many times we are unaware that these lenses are present, except in the strongest of cases, so speak and act (and type e-mails and text!) through whatever filter happens to be there at the moment. It's a gamble whether the speech/action is filtered through wisdom and kindness or something less positive like anxiety or irritation. Which means that sometimes we do, say (or type!) things that we later regret.
An underlying problem is that we blindly believe our thoughts and repeatedly take them to be ourselves. Thus we take up anything that occurs in the mind indiscriminately, though it would be much better for us to practice some discernment.
In this way we are like babies who will pick up anything and put it in our mouth. You have to watch babies very carefully when they are young because they will eat anything off the ground -- toys, stones, worms, plug points and occasionally a piece of food if they are lucky! They have no ability to discern yet between what is edible or inedible. As the adult you have to constantly be on guard, and often pry things out of their little mouths. It doesn't take long for babies to pick up some random thing and try to eat it! It also means that they end up choking a lot on the junk they pick up, and crying when it tasted bad or hurts their mouth. Does this sound familiar to you? Not just with babies, but with yourself regarding your mind?
In the same way the untrained mind will take up any thought and mind state no matter how toxic. We pick up the equivalent of indigestible stones, dirt, worms and plug points (hatred, jealousy, etc.) and consume them. It is only after we choke that we notice something is wrong. The path of practice includes learning to be aware when a thought or mind state has arisen: what is this and is this something that is wholesome or unwholesome: edible or inedible? This usually takes training, just as we have to train children about what they should put in their mouths. But we might as well learn, since otherwise we are constantly in danger of choking!
With insight meditation or mindfulness practice, we get a chance to practice this in sitting meditation, in the most basic of conditions. Sitting silently, simply breathing, then becoming aware of what is arising in the mind and in the body. What thoughts and mind states are occurring? Are they wholesome or unwholesome? Edible or inedible?
From this practice we can develop the ability to see clearly under simple conditions, which helps us to discern under more complex conditions as well. Then we can see what is in the mind when we are in the middle of a meeting, driving the car or at the grocery store. Practice can seem to take a lot of effort, but it will be well worth it for your own sake and the sake of all those you meet for the rest of your life. The unwholesome mind states can be diminished and even uprooted from the mindstream. And happiness will follow you, like your never-departing shadow.