Tafsiran Ayub 15:4: Rashi & Malbim

Surely you Surely you, who are very wise, will do away with fear by the multitude of your words.

The blasphemies Job had voiced with such eloquence and fluency in his various utterances had revealed the truth: that he had long been a heretic, one who denies free-will, life after death and God's wisdom and mercy.

and increase speech Heb. ותגרע, like (below 36:27) “He will increase (יגרע) the drops of water,” and like (ibid. 15:8), “and [did] you increase (ותגרע) wisdom to yourself.”