The Zohar, Chapter, “The Secrets of the Torah”: The founders of the city and the tower (of Babel) spoke the language of holiness, which was known to the angels, and they did not speak any other language.
And there was one language in the entire world. “One language” means the language of holiness, and because they spoke the language of holiness, they received help from the Upper Angels to complete their construction.
Therefore, nothing was impossible for them and they had the ability to accomplish anything they wanted. However, if they would not have spoken the language of holiness, they would not have received help from the angels, and their deeds would have been impure – the kind of deeds that last for just an instant and then immediately nullify themselves.
“The language of holiness” stands for the tongue of a scale which measures holiness – the correct, balanced combination of the right and left lines. The right line is bestowal, the force that comes from Above, and the left line is reception, our matter, the desire to receive pleasure.
When we find the proper balance between them, we attain the language of holiness. When this happens, the tongue of the scale shows that all our desires are for the sake of bestowal, and the right and left lines are in balance. We can then use the matter of the desire to receive pleasure in order to build our soul, because we can give it the proper structure – for the sake of bestowal.
This is the meaning of “building a city” – it is when the Upper Force, the angels, agree with and understand our actions. Stated differently, it means that we have established the proper connection with the Creator, the force of bestowal.
At every stage we use the part of the desire that we are able to, using the “language of holiness” – the middle line. This is how we continue to unite with the Creator and to attain greater similarity to Him.
We create every “rock” and “block” needed for the construction, and we use them to build the middle line, using the language of holiness. In other words, we always erect the building from below upwards, for the sake of bestowal. This is referred to as building “with the help of the Upper Angels,” the forces of bestowal.