“Abundant waters cannot extinguish the love, nor can rivers wash it away.”1"מַיִם רַבִּים לֹא יוּכְלוּ לְכַבּוֹת אֶת הָאַהֲבָה וּנְהָרוֹת לֹא יִשְׁטְפוּהָ" גּוֹ'
This verse appears towards the end of Shir HaShirim. As explained by the classic commentaries,2 Shir HaShirim is an analogy of the love relationship between G‑d and the Jewish people and, in a personal sense, between G‑d and every individual Jew. Shortly before Shir HaShirim concludes, we find this verse, which describes the love for G‑d possessed by the Jews as a whole, and by every individual Jew in particular.
The maamarim of our Rebbeim3 explain that the “abundant waters” refer to all the anxiety and preoccupation involved in earning a livelihoodוְאִיתָא בִּדְרוּשֵׁי רַבּוֹתֵינוּ נְשִׂיאֵינוּ, שֶׁמַּיִם רַבִּים הֵם כָּל טִרְדוֹת הַפַּרְנָסָה
We have translated the Hebrew טרדות as “the anxiety and preoccupation.” That term implies extensive activity, but even more so, the preoccupation of one’s mind. One feels constant pressure; he is pulled continuously in different directions.
and the thoughts concerning matters of this world.וְהַמַּחֲשָׁבוֹת שֶׁבְּעִנְיְנֵי עוֹלָם הַזֶּה
Nevertheless, despite the intensity of this preoccupation,וְעִם כָּל זֶה
they cannot extinguish the hidden love for G‑d possessed by every Jew that exists in the soul of every Jew,לֹא יוּכְלוּ לְכַבּוֹת אֶת הָאַהֲבָה הַמְּסֻתֶּרֶת שֶׁיֵּשׁ בְּכָל נֶפֶשׁ מִיִּשְׂרָאֵל,
As explained in Tanya, chs. 18-19, et al., since every Jew’s soul is an actual part of G‑d, every Jew has a natural, innate desire to bond with Him. Nevertheless, because the G‑dly soul is enclothed in the animal soul, this desire often remains hidden, submerged in the subconscious reaches of the person’s heart and mind.
“nor can rivers wash it away.”וּנְהָרוֹת לֹא יִשְׁטְפוּהָ
The term “waters” can refer to water that stands still, like the waters of the sea, which are contained and stand in one place.4 “Rivers,” by contrast, flow with a current [and indeed, at times,] a powerful current.5 Implied is that
Even when these thoughts i.e., the preoccupation with earning a livelihood and other worldly matters,שֶׁגַּם כַּאֲשֶׁר מַחֲשָׁבוֹת הַנִּזְכָּרִים לְעֵיל
are so unsettling, to the extent that they well up and flow powerfully and consistently without any interruption at all,הֵם מַטְרִידוֹת בְּיוֹתֵר, עַד שֶׁהֵן מְשׁוֹטְטוֹת בִּמְרוּצָה בִּתְמִידוּת בְּלִי הֶפְסֵק כְּלָל,
like rivers that flow incessantly,כְּמוֹ הַנְּהָרוֹת שֶׁנּוֹבְעִים תָּמִיד בְּלִי הֶפְסֵק
moving and gushing with a powerful current,וְנָיְידֵי וְאָזְלֵי בְּשֶׁטֶף גָּדוֹל,
nevertheless, they cannot wash away a Jew’s love for G‑d, (nor can they extinguish it).מִכָּל מָקוֹם לֹא יִשְׁטְפוּהָ לְהָאַהֲבָה (וְלֹא יוּכְלוּ לְכַבּוֹתָהּ).
In Torah Or,6 [the Alter Rebbe] explains that [although the simple meaning of the verse is that “rivers” is only the subject of the verb “wash away”, in an extended sense, it can be explained that] it also serves as the subject of [the verb] “extinguish.” Even when a Jew’s preoccupation with his livelihood drives him with the incessant power of a river, it will not extinguish his love for G‑d.

Summary

In Shir HaShirim, the analogy of the love relationship between G‑d and the Jewish people, it is written, “Abundant waters cannot extinguish the love, nor can rivers wash it away.” The “abundant waters” refer to tirdos haparnassah, the anxiety and preoccupation involved in earning a livelihood and the thoughts concerning matters of this world. Nevertheless, despite the intensity of this preoccupation, these thoughts cannot extinguish the hidden love for G‑d possessed by every Jew.