This is alluded to in this Posuk. And take to me Terumah, to My Name. Terumah refers to something separated. A person should separate himself from the insignificant and grab hold of that which is meaningful, to unite Hakodosh Boruch Hu and His Shechina. And take to me, My Name. Take Me to the Shechina, which is the Name of Hashem: In all places where I mention My Name (Shmos 20:24). The Targum there says, 'Where I rest My Shechina'. We should be working towards bringing a complete and true unification of Hashem to the Holy Shechina.
It is known that the Mishkan is comparable to the entire world and a person is a microcosm of the entire world (see Medrash Tanchuma Pekudei 3). A person is also like a small Mishkan. The 'Aron' of the person is the brain in which resides the knowledge of Torah and Mitzvos to remember them always and perform them and to not allow the Yetzer Hora to entice him with the physical pleasures of this world. Rather, one must remember always that he was created in this world to serve his Creator and fulfill His Mitzvos. This is stated in the Posuk, Guard yourself lest you forget Hashem, your Al-mighty (Devarim 8:11) and, And stray from the path upon which I commanded you (ibid. 11:28). The battle with the Yetzer Hora is an inner struggle, constantly within one's thoughts as mentioned by the Chovas Halevavos (Gate of Unity of Action Ch. 5) that the war with the Yetzer Hora is more difficult than any other war. He lists 10 reasons why, one of which is that this war is internal and other wars are external.
One needs great tenacity and stubborness to ward off the Yetzer Hora, like the Mishna (Avos 5:23) states, Be brazen like the leopard. Brazenness and stubborness should only be directed towards the Yetzer Hora. Towards people, Chazal say, R' Elazar ben Shimon expounded, 'A person should be flexible like the reed and not stiff like the cedar'. (Taanis 20b).
This is the allusion being made by the staves of the Aron. Inside, the staves are made of cedar wood. A person must be hard like cedar internally when fighting the inner battle against the Yetzer Hora. The staves were also covered with pure gold outside. There is nothing as malleable as pure gold. Outside, towards others, a person must be congenial with everyone. A person must remember Hashem always, and to always remember to fulfill His Mitzvos and be tenacious internally against the Yetzer Hora and congenial externally with other people. Within the rings of the Aron the staves shall remain. Do not remove them from his 'Aron', his mind, where the testimony of the Torah and Mitzvos resides. The battle of the Yetzer Hora should also not be removed from his thoughts. He must maintain constant vigilance.
