Rav Wolbe writes (Alei Shur vol. II pg. 329) that the unique blend of ahava and yirah in avodas Hashem can produce awesome results as we find with the building of the Mishkan. In Parshas Pekudei, the Torah reiterates numerous times how the Mishkan and all its utensils were built and crafted, "exactly as Hashem commanded Moshe." Had the building of the Mishkan lacked that precision, it would not have been a suitable dwelling for the Shechina.
Additionally, the Mishkan was constructed from the voluntary donations of Bnei Yisrael. Hashem could have commanded everyone to donate ten silver shekalim toward the construction just as He commanded everyone to donate a half shekel toward the purchase of the korbanos. However, He wanted every donation to be given voluntarily.
The Ramban (Shemos 35, 5) enlightens us as to why the donations had to be given in such a manner. The Torah tells us (ibid.), "Everyone whose heart motivates him should bring it - es terumas Hashem." The Ramban explains that the word "es" in this context means "with." He should bring his donation together with a Heavenly gift i.e. Hashem. In other words the proper way to read the pasuk is as follows:
Everyone whose heart motivates him should bring The Shechina together with his donation of gold, silver and copper! How does one bring the Shechina to the Mishkan? Rav Wolbe cites the Medrash (Shir Hashirim Raba 5, 2) which states that Hashem is called the heart of Yisrael. Hashem resides within our hearts. When a Jew arouses his heart to make a donation, he has in essence "aroused" Hashem also, and when he brings that donation to the Mishkan the Shechina accompanies it! Thus, the donations brought the Shechina to its dwelling place.
The construction of the Mishkan which was executed perfectly down to the last detail was a demonstration of Bnei Yisrael's yirah. The voluntary monetary donations made toward the building of the Mishkan were a manifestation of Bnei Yisrael's ahava. Together, they succeed not only in creating an abode that was suitable for the Shechina, but actually bringing the Shechina into that abode.
Every mitzvah requires the two facets mentioned above. Firstly, it must be performed with fear, i.e. precisely how Hashem wishes it to be performed. Additionally, one should arouse his heart to perform the mitzvah with love and out of a voluntary desire to serve Hashem. From the Mishkan we can see the awesome results such a mitzvah can produce.