Two Levels of Concentration

1. Momentary concentration: the act of the mind's growing still for a moment, like a person walking along: One foot takes a step while the other foot stops still for a moment before taking the next step.

2. Threshold concentration: the act of the mind's settling down deeper than that, like a person who is walking along, meets with something, and stops to look for a moment — with neither foot taking a step — before he resumes walking.

These two types of concentration are not without their dangers or enemies. If you're not proficient enough at them, they may deteriorate — or you may get hooked on them. The dangers that arise in the wake of these types of concentration are (a) growing attached to the meditation syllable, having no sense of when to stop repeating it; (b) being taken in by the five forms of rapture; (c) playing around with visions and signs that appear, regarding them as especially true or potent.

All of these phenomena, if you're wise to them, can help lead to the paths and fruitions leading to nibbana. If you aren't wise to them and become attached to them as something special, the mind is sure to fall for the various forms of rapture and to start drifting astray. You might start behaving under the influence of what you see in your meditation or intimate to others that you have invincible powers or clairvoyant abilities. All of this can destroy your concentration. Your mindfulness and self-restraint will become weak and you'll drift along under the influence of whatever occurs to the mind — self-indulgent, dreaming, and drifting. These phenomena thus become your enemies, killing off the level of concentration that's resolute and endowed with the discernment capable of seeing through all three levels of being.

This is why the above phenomena are termed enemies. When we begin meditating, though, we have to start out by clinging to these very same enemies. But in clinging to them, don't be complacent, because they're only a path. Ordinarily, when we walk along a path, we don't have to pull it up and carry it along behind us. We just leave it where it is. In the same way, the meditation syllable, rapture, and visions are things we have to pass through, but not that we have to latch onto — thinking, for instance, that we've already reached the goal.