1) Perceiving With Emunah
Devarim 4:6 "…for it is your wisdom and understanding in the eyes of the nations…"
Chazal tell us that this verse refers to the calculation of the “seasons and constellations”, i.e. the determination of the start of the Jewish lunar months [when the moon starts to wax again after a two week period of waning]. This is the time when there is “filling of the blemish of the moon so that it exhibit no lack and that its light be as the sun” (prayer of kiddush levanah). This alludes to emunah/faith becoming full and complete with a completion without blemish or lack at all, becoming as the light of the sun.
This means that we must try to be very strong in our emunah – which relates to the moon – in matters that the intellect is unable to comprehend and attain. Emunah should be so powerful within us, and so illuminate the intellect, as if we actually see and understand intellectually. This is the main way of complete emunah: It should appear to us as if we are really looking, with our eyes. This is the concept of the “light of the moon as that of the sun”.
Orach Chaim Hilchos Rosh Chodesh 6:1
2) Doing Mitzvos Simply
Devarim 7:7 “…you are the least of all the nations”
The explanation is that Hashem says: “You behave with self-effacement when I bestow good upon you” (see Rashi). This means that when Hashem shines upon the Jewish people an illumination of flashings of His G-dliness, they do not engage in investigative intellectual quest into the matter. Rather, they become invigorated with emunah/faith and immediately seek Hashem.
This is expressed in Shir HaShirim/The Song of Songs (1:4): “Draw me: We will run after You”, that we run after Hashem right after He starts drawing us towards Him. Thus, Rashi explains: “I heard from Your emissaries that You wish to draw me towards You, and I immediately ran after You”.
But soon after we start to pursue Hashem, so to speak, He appears to flee and conceal Himself, as expressed by (ibid. 8:14): “My Beloved One fled…”, corresponding to (ibid 5:6): “I opened to my Beloved One, but He turned away and left…” At that point we then have to start a measured and orderly pursuit after Him, seeking Him and serving Him with actions and good deeds with simchah/internal happiness, until we merit finding Him with ever increasingly wondrous revelation.
This relates to the verse: “Everything that Hashem has spoken, we will do and understand”. The meaning is: ‘All that Hashem instructed, we will perform immediately, without any question or investigation at all and afterwards we will comprehend’. For it is through doing the mitzvos with emunah, simplicity and simchah that we merit later understanding and attaining great and awesome concepts.
On the other hand, the idol worshippers and heretics wish to precede the “understanding” to the “performing” since they are slaves to their earthly desires and evil character traits. They wish to immediately attain the fruits of philosophical investigative discovery of G-dliness and the reasons behind the holy mitzvos. Only then might they possibly hasten after some mitzvah or other - if they perceive its spiritual light at root that illuminates all the spiritual worlds.
Orach Chaim Hilchos Nefilas Apayim U’Kedushah DeSidrah 4:13, (according to Otzar HaYirah –Emunah 17)