大方廣佛華嚴經搜玄分齊通智方軌 4.17

4.17

一釋名者，無礙力說法成就利他行，故名善慧地。

First, explaining the name: because through the power of unhindered speech in preaching the Dharma he accomplishes the practice of benefiting others, it is called the Bhūmi of Good Wisdom (Sādhumatī-bhūmi).