What is the difference between the meditative concentration of non-Buddhists who do not observe the precept against killing and that of the Buddhist gate?

Samādhi carries the merit of samādhi. In meditative concentration where the precept against killing is not observed, the merit of samādhi is diminished. However, as the power of concentration deepens, the bodily, verbal, and mental actions one creates become fewer and fewer, until one no longer creates bodily, verbal, or mental actions at all. At that point, even these non-Buddhist meditative concentrations are concentrations that keep the precepts—precepts kept without being deliberately kept, and morality arises naturally. Such morality is purer than the five precepts and the eight precepts with one meal per day that Buddhists observe, and even purer than the bodhisattva precepts observed by most people.

Because they possess such deep meditative concentration in which no precept is violated, when non-Buddhist practitioners hear the Buddha teach the Dharma, in that very moment they contemplate and immediately attain the fourth fruit of arhatship, without having to pass through the first, second, or third fruits. Can Buddhists compare with that?

Although non-Buddhist meditative concentration cannot eliminate self-view or eliminate afflictions, it can subdue the self and subdue afflictions, leaving them still faintly connected to the five aggregates as self, still faintly connected to the afflictions. Then, when the Buddha finally expounds the Buddhadharma, the non-Buddhists deeply believe in the Buddha, truly take sole refuge in the Buddha, and swiftly attain realization; their self-view and afflictions are no longer faintly connected but are thoroughly eliminated.

If the shallow concentration cultivated by Buddhists cannot subdue the self and cannot subdue afflictions, then there is still a long road to travel before afflictions can be eliminated.