大乘入道次第開決 1.60

1.60

說法自在獲得等者。以前諸地無礙智於說法時則有過失。今得無礙說法自在既無過失故名無罪。

As for "attaining mastery in expounding the Dharma, etc.": on the preceding bhūmis, unimpeded knowledge still involved faults when expounding the Dharma. Now, having attained unimpeded mastery in expounding the Dharma, because there are no faults it is called "faultless."