Likutei Moharan 6:4/ליקוטי מוהר"ן ו׳:ד׳

14. Now, when a person wants to walk the pathways of repentance, he must be baky (expert) in Halakhah. This demands that he have two types of expertise: baky b’ratzo (expert at “running”) and baky b’shov (expert at “returning”). As stated <in the Zohar (III, 292a)>: “Deserving is he who enters and exits.” This corresponds to (Psalms 139:8), “If I ascend to heaven, You are there”—an aspect of ascending, of being expert at running; “and if I make my bed in Hell, here You are”—an aspect of descending, of being expert at returning.

2This is (Song of Songs 6:3), “I am my beloved’s, and my beloved is mine.” “I am my beloved’s” is the aspect of ascending; “and my beloved is mine” is the aspect of descending. {This is the hidden meaning of the meditations of Elul,} and this is the essence of His glory.

3And this is (Isaiah 58:13), “and you honor [the Shabbat] by refraining from your routine ways.” “Ways” is plural, indicating ascending and descending. When a person possesses these two types of expertise, then he is walking the <true> pathways of repentance, and merits the above mentioned <Godly> kavod. As it is written, “and you honor it by refraining from your routine ways”—i.e., he attains Keter, for there can be no kavod without a kaf. Then, the right hand of God is outstretched to accept his repentance (cf. Sifri, Deuteronomy 3:29 ; Tachanun Prayer).

4{This is the hidden meaning of the kavanot (meditations) of Elul}.