ירמיהו, פרק ט׳, פסוק ג׳

A society collapses when basic trust disappears. In a deeply broken social reality, the foundational bonds of family and friendship shatter, leaving individuals completely isolated and vulnerable to betrayal. The warning against relying on others addresses the two closest circles of human connection: friends and brothers.

Regarding friends, people are advised to actively guard themselves. This protection specifically means holding back from sharing the secrets of the heart. In such a corrupt environment, companions are prone to gossip and will readily expose private matters, ultimately causing real harm to those who trusted them [מצודת דוד, מלבי״ם, שטיינזלץ].

The breakdown of trust extends even deeper into the family unit, where a person cannot even rely on a close brother born of the same parents. Family members act with trickery and deceit, constantly trying to trip each other up and twist the right path. This behavior is compared to someone walking in crooked, confusing circles just to trick someone else [מצודת דוד, מצודת ציון, מלבי״ם, שטיינזלץ]. Alternatively, this deceit is understood as setting a hidden ambush [רש״י]. The concept of such family trickery draws directly from the ancient conflict where Esau accused Jacob of deceitfully taking his place [רד״ק, מלבי״ם].

Because of these different dynamics, there is a careful distinction in how one must approach a friend compared to a brother. With a friend, a person must be on active defense to prevent the actual harm that comes from leaked secrets. However, the warning regarding a brother focuses on a complete lack of reliance. A brother might not actively plot to cause direct harm, but his sneaky nature means he simply cannot be trusted to offer help or do anything good [מלבי״ם].