Our Gemara on Amud Aleph through Beis relates several teachings of Bar Kappara, which at first do not seem linked, but we shall see are connected:

1. There are two optimal days for marriage, Thursday and Friday. Thursday because the blessing for the fish to be fruitful and multiply was stated (Bereishis 1:22), and Friday because the blessing for Man was stated (ibid, 28).  The preference is for the marriage day to be Friday if not for certain technical concerns, because “the day on which the blessing of man was stated is preferable.”
2. The handiwork of the righteous is greater than the creation of heaven and earth, as with regard to the creation of heaven and earth it is written: “My hand also has laid the foundation of the earth, and My right hand has spanned the heavens” (Isaiah 48:13). There, hand is written in the singular. Whereas with regard to the handiwork of the righteous it is written: “The place which You have made for Yourself to dwell in, Lord, the Sanctuary, Lord, which your hands have established” (Exodus 15:17). The reference is to the Temple, which is the handiwork of man, and hand is written in the plural.
3. Bar Kappara taught: What is the meaning of that which is written: And you shall have a peg among your weapons [azenekha]” (Deuteronomy 23:14)? Do not read it as: Your weapons [azenekha]. Rather, read it: On your ear [oznekha], meaning that if a person hears an inappropriate matter, he should place his finger, which is shaped like a peg, into his ears….What is the reason that they are pointed like pegs? It is so that if a person hears an inappropriate matter, he will place his fingers in his ears. 

These seemingly unrelated teachings are actually all connected.  According to the commentary of the Chasam Sofer, Bar Kappara was meditating on the ultimate question of whether Man is worthy of creation in comparison to animals.  On the one hand, animals do not sin and fulfill their purpose in creation fully and instinctively.  This brings glory to the Creator.  On the other hand, humans by virtue of their potential to sin, which indeed they often do, when they voluntarily choose to elevate creation by doing good, bring greater honor to the Creator.  In essence, the risk-reward ratio by man is greater than beast.  The greater potential for sin also leads to greater potential for honor for the Creator.  It is fascinating how certain ideas are constants in the Universe, from physical to spiritual.  No matter what vulnerability a person is considering, intimacy, religion or money, the greater the risk, the greater the benefit.

In any case, the Chasam Sofer explains these three teachings along these lines. The question of whether the blessing of Fish or Man is superior, is expressing this idea about Man’s potential superiority for the ability to choose good, but the often actual inferiority to beast by choosing evil.  The assertion that the handiwork of Man in making the Temple is superior to God’s handiwork of creating Heaven and Earth also expresses this idea.  Though God’s absolute goodness and beneficence is technically superior, Man’s choice to bring God into the world as expressed metaphorically by the building of the Temple, is superior in the final analysis.  Lastly, the discussion about placing the fingers in the ear to forestall hearing forbidden matters addresses the claim that humans may have against God: “How can you expect us not to sin when we have such powerful drives and instincts?  Moreover, our ears can hear things and we do not even have the ability to shut them!”  The response is, “True, but, you were given tools and “weapons” even regarding this matter.  You can use your fingers to shut your ears. That is, you can still garner your resources to overcome your instincts.    

Nefesh HaChayyim (1:4) quoting several midrashim also makes this point.  The Beis Hamikdash is a representation of Man’s ability to bring the holy into this world.  It is human handiwork in order to complete God’s mission.