Kabbalah sa 1 Cronica 28:9: Ohr Ne'erav, Baal HaSulam's Introduction to Zohar, The Wars & Reshit Chokhmah

We need cite no farther. There can be no doubt that the intention of Rabbi [Moses] was to include in this commandment [the command] to understand the order of being [stemming] from Him [as far as] human understanding [can comprehend]. This can be proven from the length of his explanation of this matter, [which encompasses] two entire paragraphs.¹Maimonides, Mishneh Torah, Hilkhot Yesodei ha-Torah 2:2, 12. Cf. Guide of the Perplexed, introduction and 3.28. It is also included in his brief statement. When he said, “to know that there exists a First Cause which brought into being all that exists,” [he indicated that] one needs to know as well the order of the bringing of the existents into being. He also specified the scriptural verse I am the Lord your God, meaning, “you must ascertain concerning Me, the Lord, [that I am] your God.” This refers to Providence, which [extends] from the highest beings to the creation of lowly man. There is no doubt about this, for how is it possible to understand the word to know [except to assert] that it indicates belief in the existence of God? This being so, he should have stated, “[It is] a positive commandment to believe that God exists.” [However,] he did not state this, but rather [utilized the wording] to know that there exists. Evidently, [then, this commandment] requires the acquisition of actual knowledge concerning God according to the power of the human intellect. Thus Scripture states, Know the God of your father and serve Him (I Chron. 28:9). [This verse] teaches that in order to serve [God] properly one needs [to acquire] knowledge concerning Him—that is, knowledge of His sefirot, His conduct with them, and His unification with them.²The nature of God’s relationship with the sefirot was the subject of debate among Kabbalists. Was God co-extensive with the sefirot, or did they constitute instruments which He utilized? In his analysis of this problem, Cordovero tended to hedge his bets somewhat. See Yosef Ben-Shlomo, The Mystical Theology of Moses Cordovero [Hebrew] (Jerusalem: Mossad Bialik, 1986), chap. 2. That is proper worship, [which causes] the unification of the Holy One, blessed be He, and His Shekhinah. That is why [the verse] specifies and serve him (va-’avadahu), which signifies and serve hu [i.e., heh vav, indicating] the Holy One, blessed be He, and His Shekhinah.

In order to clarify these [questions] in their entirety, we must initially make some inquires (about the Creator) not in areas that we are forbidden to discuss, in other words about the Creator's essence, which we have no knowledge whatsoever, but in an area where such knowledge is a Mitzvah, that is, concerning His actions. As the Torah commands: "Know the G-d of your forefathers, and worship Him". And it is also written, in "Shir HaYichud": "You [G-d] are known through your actions".

From this [passage] there is another proof that the essence of [Scripture’s] statement Know the God of your father (I Chron. 28:9) refers to the pursuit of this science. [Thus the passage] stated, “to know their Master.” It also appears that one must pursue the knowledge of hidden things with great punctiliousness, concentration, and analysis. This is the opposite [of the opinion] of would-be Kabbalists in our generation who say that one need not be exact in this science.