Mallans
Malla Sutta  (SN 48:52)

I have heard that on one occasion the Blessed One was staying among the Mallans. Now, there is a town of the Mallans named Uruvelakappa, and there the Blessed One addressed the monks: “Monks, as long as noble knowledge has not arisen in a disciple of the noble ones, four faculties are not stable, four faculties are not firm; but when noble knowledge has arisen in a disciple of the noble ones, four faculties are stable, four faculties are firm.

“Just as—as long as the ridge-beam of a house with a ridged roof, is not in place—the rafters are not stable, the rafters are not firm, but when the ridge-beam of the house with a ridged roof is in place, the rafters are stable, the rafters are firm; in the same way, as long as noble knowledge has not arisen in a disciple of the noble ones, four faculties are not stable, four faculties are not firm; but when noble knowledge has arisen in a disciple of the noble ones, four faculties are stable, four faculties are firm. Which four? The faculty of conviction, the faculty of persistence, the faculty of mindfulness, & the faculty of concentration.

“When a disciple of the noble ones is discerning, the conviction that follows from that is stable. The persistence that follows from that is stable. The mindfulness that follows from that is stable. The concentration that follows from that is stable.”

See also: AN 3:110