One of the mitzvos in this sidra is that of Pidyon HaBeyn, the redemption of the firstborn son via  money given to a kohen.  

The Talmud, at the end of Pesachim,* relates that R. Simlai was asked at one such occasion  regarding the two blessings that it necessitates, הבן פדיון על and שהחיינו. The first is obviously to be  recited by the father of the child. But who ought to make the second – the kohen, because he earns  the money, or the father, because he fulfills this uncommon mitzvah? As he did not know how to  respond, the question was brought to the beis midrash, where they decided that the father recites  both blessings. And, indeed, the Talmud fixes this as the normative law.  

There are three questions that I would raise about this passage. 1) If it is obvious that the blessing  of הבן פדיון על is recited by the father, why mention it? 2) Why is the mitzvah called הבן פדיון,  redemption of the son, and not, seemingly more accurately, הבכור פדיון, redemption of the firstborn?  3) Similarly to our first question, why need the passage conclude that the father recites both  blessings if the whole question only revolved around the second one?  

I would suggest that this can be resolved with the following thought. The verse states את ברך' וה בכל אברהם, And Hashem blessed Avraham with everything.** The Sages provide two explanations  for this unusual language. One is that it refers to Avraham’s son (as ל"בכ and ן"ב share the same  numerical value), Yitzchak. Another is that it refers to his daughter, whose name was Bakol.*** As  the Gur Aryeh observes, the second explanation is understandable, but according to the first one,  why doesn’t the verse simply say straight out that he had a son? Furthermore, is this a dispute  about a historical fact?  

The Attribute of Malchus functions in two modes. In its superior one, it is connected with the rest  of the supernal realms. It is then that it has the title ן"ב, which is the value of one of the permutations  of the Tetragrammaton, as its connection with the rest of the system is represented by the complete  four-letter Name. In its inferior mode, when it is disconnected, it is merely the feminine quality of  Malchus; hence it is known as ל"בכ, the “daughter.” Suffice it to say that both of these modes were  fundamental in laying the foundation of our universe with both its positive and negative  dimensions.  

As such, on a deeper level, both interpretations of the word בכל are correct; they reflect two  different perspectives. Now, kabbalisticly, the purpose of the Pidyon HaBeyn is to elevate the Malchus from its lower  mode to its higher one. This is accomplished through the participation of the kohen, as he stands  for Chessed, the positive quality which can empower such elevations. What role does the father  play in the process?  

The short answer is that in Kabbalah the father, or Abba, is indicative of abstract thought.**** It is  that thought which has the power to navigate a destructive tendency onto the correct path. The  biological father has a similar role in the redemption of his son. It now makes sense as to why the   .על פדיון הב"ן as formulated is blessing 

The function of the blessing of שהחיינו also becomes understandable. When Malchus was in its  lower mode, the world was in a state of destruction and disarray. It is only with the advent of the  higher mode that it stabilized. Thus, when this process plays out in the micro during a Pidyon  HaBeyn, it is appropriate to recognize the cosmic rectification playing out with the thanks to  Hashem that “He has kept us alive and maintained us.” And הזה לזמן, to this time, is a reference to  Malchus, which is associated with the concept of time.  

With this background, we can unlock the passage in Pesachim. The question asked of R. Simlai  was to the point. That which the father makes the first blessing is indicative of the critical role that  the father plays in the cosmic process redemptive latent in the Pidyon HaBeyn. It would seem to  follow that this should necessitate of him the blessing of שהחיינו as well. On the other hand, the  kohen also assumes an essential role, standing in Hashem’s stead. Considering that the child is akin  to the Shechinah, which is allegorically the “daughter” of Hashem, the ultimate benefit of the  redemptive process is, so to speak, unto Him, much as any material earning of a young, single  daughter is the property of her father. The argument could therefore be made that the celebratory  שהחיינו be made by the Kohen.  

The Sages responded that the role played by the father is indeed the more significant, as  demonstrated by his recital of the first blessing.  

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* 121b.
** Bereishis 24:1.
*** Baba Basra 16b.
**** Crea on requires an abstract plan and its physical execu on. In the crea on of a child, it is the father who provides
the raw material and the mother who develops it into reality.