Likutei Moharan, Part II 85:1/ליקוטי מוהר"ן·תנינא פ״ה:א׳

1Luzim nuts hint to the concept of Leah. She is at the back of the neck, the first wife. Then afterwards one enters the Holy Temple, which is the concept of Yaakov called it Beit-El (the House of God) (Pesachim 88a).

2This is as Rashi explains, that through luz one enters Beth-El (see Judges 1:24).

3This is “Nachamu, nachamu (Console, oh console)” (Isaiah 40:1), [as] twice NaChaMU has the same numerical value as KaDKoD (fontanel)—which is the concept of the back of the neck through which one enters the House of God.