妙法蓮華經玄贊 7.13

7.13

贊曰：三客利豐廣。「商」賈也，通四方之珍異曰商，坐賣曰賈。「估」市稅也。行曰商，坐曰賈，客名通上。往來六趣以利群生曰商，住淨土、人、天以化物曰賈。遍三界厘市行其稅利曰估。利豐客廣，故遍三界皆有佛法。

The Commentary says: The third is that his mercantile profits were abundant and broad. Shang and gu mean merchants: those who travel through the four quarters with rare treasures are called shang; those who sit and sell are called gu. Gu also means marketplace taxes. Traveling is shang; sitting is gu. The name ‘client/merchant’ applies to both. Moving back and forth through the six destinies to benefit the multitude of beings is called shang; dwelling in pure lands, or among humans and devas, to transform beings is called gu. Levying taxes and gaining profit throughout the marketplaces of the three realms is called gu. Because profits are abundant and clients are broad, everywhere throughout the three realms the Buddhadharma exists.