Mechanics of karma.

Karma is intention and that which is produced through intention.

Intention is mental action-

It gives rise to two types: physical and verbal action.

Vasubandhu

When we sit down to meditate we are directly working with our karma. Each meditation session, whether it involves meditation with an object or objectless meditation, must start with a clear intention. 

Suppose we were to meditate on the breath using a vague intention, "I'm going to meditate on the breath." If we set the intention to meditate on the breath, we would find that our focus might start with the breath at the nose, then drift to the breath filling our lungs, and continue to wander to the rise and fall of our belly. An unclear intention leads to mental wandering and distraction. If our intention is unclear, the actions that follow are sloppy. 

Vague intentions create careless actions, which perpetuate unforeseen karmic consequences.

In meditation, we have an opportunity to shape our karma and it starts with intention. 

Before, we were mindless, wandering and distracted. Now we are present, alert and aware. We are shaping our mind, like a potter working with clay. Who we are is not fixed. What we stand for, what we represent, all of that is malleable like a block of wet clay. We are able to change direction, shift our posture, plot a new course. 

And it all starts here, with a clear intention. 

Through intention, we plant the seeds of virtues like being present, mindful, open and aware. We can develop equanimity, peace and gentleness towards ourselves and others. We can be more caring, generous and kind.

While we are operating within the confines of mind, we must work with karma. That starts by working with intention.