A solemn oath taken in exile captures a profound loyalty to the memory of Jerusalem. The captives bind their physical ability to produce voice and song to their constant memory of the ruined city, declaring that national mourning must always take priority over any personal happiness. The primary approach among commentators views the image of a silenced tongue as a total loss of the ability to speak and sing. Because the tongue is the specific organ responsible for expressing songs [אבן עזרא], the exiles express that if they were ever to forget Jerusalem, it would be better for their power of speech to vanish completely, leaving them unable to sing or play music [רד״ק, ביאור שטיינזלץ]. In the harsh reality of captivity, this vow also serves as a quiet apology. If the exiles are heard singing in a foreign land, it does not stem from any joy in their hearts, but is rather a forced act demanded by their captors [מאירי].
On a deeper spiritual level, the destruction of the city is understood as a severe blow that stripped wisdom and knowledge away from the people. In this context, the roof of the mouth represents the secret of wisdom, while the tongue symbolizes the secret of knowledge [חומת אנך]. Another perspective suggests that silencing the tongue hints at the hidden nature of the future redemption, meaning the exact time of salvation remains a secret that must not be spoken aloud [אלשיך].
The commitment to remember Jerusalem requires a constant verbal recognition of the city's destruction and the ongoing mourning for it [רד״ק, אבן עזרא, מצודת דוד]. Pledging to elevate Jerusalem above all joy means positioning the memory of the destruction at the very beginning of every personal celebration [מצודת ציון]. By mentioning the tragedy of Jerusalem before a celebration even begins, it prevents the intense enthusiasm of the event from making people forget the ruined city [מצודת דוד]. Consequently, introducing this memory immediately restrains and diminishes the personal joy [מאירי]. Looking ahead, placing Jerusalem at the peak of joy also hints at its ultimate destiny. While the Temple was the focal point of joy for God in the past, in the future, the spiritual quality of Jerusalem will rise even higher, transforming the city into the absolute summit of joy for the entire world [אלשיך].