The parable used to explain that every person is shown the future Beis Hamikdash is that of a garment. This is because there are different levels of holiness within the Beis Hamikdash. Each section contains its own particular holiness, corresponding to a specific level in the Beis Hamikdash Above. In this respect, the Beis Hamikdash is like a garment, which has a specific connection to the holiness contained within it.
The well-known explanation of the Rav of Berditchev teaches that Shabbos Chazon is called by this name because on this Shabbos every person is shown the future Beis Hamikdash. He illustrates this with a parable of a father who sewed a garment for his son, and the son tore it. The father sewed him another garment, and he tore that one as well. The third time, the father sewed a garment but did not give it to his son. Instead, he would show it to him from time to time and tell him that when he would be worthy, he would receive the garment.
It is necessary to understand: why is the parable specifically from a garment and not from a house? A house is permanent and would seemingly be more similar to the Beis Hamikdash.
The explanation is that a garment has an advantage over a house. A garment is tailored according to the measurements of the person, and therefore it is connected to that specific individual. A house, by contrast, is a more distant surrounding environment. From seeing a house, one cannot know the form or measurements of the person who lives in it.
There are different levels of holiness in the Beis Hamikdash. Each section contains its own unique holiness, corresponding to a particular level in the Beis Hamikdash Above. In this sense, the Beis Hamikdash is like a garment, for each part has a specific connection to the holiness that is present within it.
This is especially true regarding the Third Beis Hamikdash. From the Beis Hamikdash, this revelation will affect the entire world, for in the future the prophecy will be fulfilled: “All flesh together will see that the mouth of Hashem has spoken.” “Speech” refers to the Divine utterance from the Ten Utterances that is present within every individual created being. In the future, the specific Divine speech within each created being will be openly seen.
The idea of a garment is also connected with a person’s Divine service. Seeing the garment inspires one “to follow the straight path until it becomes known that it has become like second nature to him.” When serving Hashem becomes like one’s nature, then a person serves Hashem in every form of service. For if he serves Hashem only in one particular direction, this shows that Divine service has not truly become his nature; rather, he is serving Hashem only through his existing natural tendency. True service means serving Hashem with every detail of the soul, like a garment that is fitted to every part of the person.