Ambrose of Milan, on Ps 133:1

“Behold now bless ye the Lord, all ye servants of the Lord: Who stand in the house of the Lord, in the courts of the house of our God.”

“Sitting we speak against others, but standing up we praise the Lord, as it is said; "Behold now, praise the Lord, all ye servants of the Lord; ye that stand in the house of the Lord." He who sits, to speak of the habit of the body, is, as it were, dissolved by ease, and relaxes the energy of his mind. But the careful watchman, the unwearied scout, the wakeful sentinel who keeps the outposts of the camp, these stand. The brave warrior also, who would prevent the designs of his enemy, stands ready in his rank ere he is looked for.”

Imported from an open dataset — not yet checked against the printed edition.