阿彌陀經通贊疏 2.13

2.13

贊曰：第六徵國名號。故者所以義，前標極樂之名，未彰極樂之相，不覩勝妙難為發心，將欲顯示淨方，故乃自徵國號也。

The Commentary says: Sixth is inquiring into the name of the country. "Reason" has the sense of 'wherefore'. Earlier, he marked the name of Sukhāvatī, but has not yet displayed the characteristics of Sukhāvatī; without seeing its excellence and wondrousness, it is difficult to give rise to the mind [of aspiration]. Intending to display the pure realm, he therefore inquires into the country's name himself.