The true power of human speech lies not merely in the information shared, but in the manner of its delivery and its impact on the listener. A sharp contrast exists between the wise and the foolish, revealed not in the raw facts they possess, but in how they choose to express themselves. One path offers refined, healing communication, while the other releases an uncontrollable flood of nonsense.
The primary approach among commentators is that wise individuals focus heavily on the presentation of their knowledge. Their communication involves a deliberate process of perfecting and beautifying their words [מצודת ציון, אבן עזרא, ביאור שטיינזלץ]. They speak with precision, brevity, and clarity, teaching gently so that their wisdom becomes attractive and accessible to those listening [מצודת דוד, עמנואל הרומי, אמרי דעת]. Beyond simply sounding pleasant, this refined communication serves a practical purpose. It corrects misconceptions, clarifies difficult concepts, and resolves the lingering doubts of the audience [רלב״ג, אמרי דעת].
Exploring a deeper layer, [מלבי״ם] distinguishes between proven knowledge and received wisdom. He notes that wise people use rational, logical speech to clarify traditional wisdom until it becomes as absolute and clear to them as tangible, proven facts. Taking a more theological perspective, [אלשיך] explains that the wise recognize how God's absolute foreknowledge does not contradict human free will. They accept that His knowledge is entirely beyond human comprehension, and through this understanding, they elevate human intellect to its proper place.
In sharp contrast stands the unrestrained speech of the foolish. Even if a foolish person acquires education and gathers facts, everything that leaves his mouth turns into nonsense [ביאור שטיינזלץ]. Instead of carefully crafted words, his speech is compared to an overflowing spring, pouring out endless amounts of foolishness without any order or restraint [מצודת ציון, אבן עזרא, מצודת דוד, עמנואל הרומי]. This uncontrollable flood actively harms the listeners by injecting them with doubt and a spirit of confusion [רלב״ג].
Interestingly, this foolishness does not necessarily stem from genuine ignorance or a lack of internal understanding. Often, a fool knows the truth but allows his physical desires to create artificial doubts [מלבי״ם]. He might even use philosophical excuses, such as arguing that God's foreknowledge cancels out free will, simply to avoid taking responsibility for his own wrongdoings [אלשיך]. Ultimately, the foolishness exists entirely in his mouth rather than his heart, as he uses his speech to fight against a truth he already privately acknowledges [מלבי״ם].