Even though building a House for G-d is a Torah mitzva (Rambam, Hilchot Beit Habechirah) and the Torah will never change (Rambam, Thirteen Principles), there are some differences about the way the Temple was built at different times, in accordance with the words of G-d as handed down by the prophets.
Therefore, the plan of the Tabernacle in the desert was not the same as that in Shilo, and they were not the same as the designs of the First and Second Temples, or the Third Temple of the future which appears in the prophecy of Ezekiel. The reason for this is that the Temple is a reflection of the heavenly world in our world, "like the image that you were shown on the mountain" [Exodus 25:40] – something akin to the ideal world of Plato. The spiritual world changes form to correspond to changing times, and therefore the appearance of the Temple on the earth changes too.
One of the details that is different between the Tabernacle as described in the Torah portion of Teruma and the Temple of Solomon as described in the Haftarah of Teruma is that in the Tabernacle there are no windows, while the Temple built by King Solomon does have some. Thus, the Divine inspiration in the desert was meant for Israel exclusively, without any contact with the other nations of the world, because at that point Israel was just coming into existence and had the experience of an intimate wedding ceremony with the Creator – "The love of our betrothal, when you followed Me into the desert." [Jeremiah 2:2]. When Solomon arrived, the time had come for the active universal influence of the Children of Israel, when the entire world came to hear the wisdom of Solomon. This was therefore the proper time to make windows in the Temple, indicating a point of contact between Yisrael and the other nations.
The passage describes "transparent blocked windows" [Kings I 6:4]. Targum Yonatan writes that the windows were "open on the inside and blocked on the outside." This is an indication the holy was able to absorb from the profane – that is, the Jews absorbed from the non-Jews. This is also what Rav Kook implies in Orot Hatechiyah (Chapter 15). However, see the RADAK: "The sages felt that the opposite was true: the windows were open to the outside and blocked on the inside. This is to say that the people of Yisrael had no need for the light of the world." According to this, the windows indicated that holiness was sent out from the holy site to the outside, without being influenced by the outside (this corresponds to the earlier commentary of Rav Kook, Ein Ayah Bikurim 27).
We can say that there is no dispute in principle between the two approaches. Rather, the first one describes the actual situation. The nation of Israel is not afraid of external influences when the Shechina (the Divine spirit) has appeared within it. The second commentary describes the essential difference between Israel and the other nations, something which grants Israel a feeling of security.
The Metzudot explains that the windows were made of glass, at one and the same time both transparent and blocked. This commentary seems to combine the two above approaches described above. However, in order to combine the external and internal influences it is necessary to create new technology, such as glass, which is invented at a later stage, as part of the world's development.
Source: “AS SHABBAT APPROACHES” – a biweekly column in Shabbat B’Shabbato (Zomet Institute) See: http://www.zomet.org.il/eng – Teruma 5775, issue 1563.