Our Mishna on Amud Aleph discusses the qualifications of two different kinds of bird offerings:

“He shall bring his offering of doves, or of young pigeons” (Leviticus 1:14). 

“The age that is fit for sacrifice in doves, mature birds, is unfit for sacrifice in pigeons, immature birds; the age that is fit for sacrifice in pigeons is unfit for sacrifice in doves. At the intermediate stage of the beginning of the yellowing of its plumage (see 22b), a bird is unfit both as this, a pigeon, and as that, a dove, since it is no longer a fledgling but is not yet a mature bird.”

In general, the Jewish people are compared to the dove. The Gemara Shabbos (49a) states:

“The congregation of Israel is likened to a dove, as it is stated: ‘You shall shine as the wings of a dove covered with silver and her pinions with yellow gold’ (Psalms 68:14). Just as this dove, only its wings protect it and it has no other means of protection, so too the Jewish people, only mitzvot protect them.”

Midrash Tanchuma (Tetzaveh 5) offers several additional ways in which the Jewish people are compared to the dove: in that it is bonded to its mate forever, and it eventually returns back to its coop. Finally and chillingly, just as a dove won’t fight its death but sticks its head out to be slaughtered, so the Jewish people will willingly martyr themselves for the Torah.

Returning to the bird sacrifices, conceptually we are discussing two kinds of birds, one which is meant to be offered in a mature stage, and another which is meant to be offered in its young stage. Additionally, there is a middle stage, a transition point of sorts, where it is neither old enough nor young enough, and not kosher for either bird sacrifice. 

Understanding that the dove is symbolic of the Jewish people, Noam Elimelech (Shlach) adds a dimension to this idea about a young stage and an older stage, and that each stage has its appropriate offering. He says this refers to two kinds of tzaddikim. A mature tzaddik can safely engage with this world and others. He can become a positive influence, without being influenced. The less mature tzaddik needs to retreat from the world in order to develop his internal capacities.

It is not just that these two models exist but they each must have the self-honesty to recognize who is whom, because it is unkosher for them to behave as the other. That is to say, the tzaddik who is capable of engaging with the world is not allowed to retreat. At the same time, the tzaddik who needs to retreat from this world needs to assess it correctly and should not engage.

Furthermore, the middle stage is not kosher for either. Noam Elimelech explains that this means if the tzaddik notices personal pride in his actions (the “yellowing feathers”) then neither course of action is kosher. I believe he means to say that whether he chooses the path of asceticism or engagement, if he becomes prideful, it is a sign that his assessment of himself is inaccurate and without pure motives.

Another thought which occurs to me is that trying to hold a middle stage between asceticism and engagement may defeat both purposes and therefore is invalid. That is to say, even though generally speaking, the middle path is usually the best (Deos 1:4), that is still a relative term. With any particular trait, one should aim to be balanced, and not on the extreme. However, the Rambam also speaks of the idea that there can be a strategic choice to go to the extreme (ibid 2:2) in order to correct and balance out a weakness or personality flaw. When that choice is made, while even in that choice there might be some relative moderation, it also requires acceptance and recognition that there is a reason to go to the extreme. And in taking that choice, trying to be in both places at once will not serve either purpose. 

Similarly, the message for the two types of tzaddikim might be that one who feels he needs to retreat from the world, if this assessment is accurate, has to be able to follow through with consistency. Likewise, the one who believes he needs to engage with the world should be fully committed to that course of action and not waffle back-and-forth. Because each of these styles of relating to the world is a particular path and can have validity when properly applied. The behavior should not be wishy-washy and inconsistent, in order to achieve the desired goal. To one day retreat and one day engage is neither kind of Tzaddik. Instead he’s just a confused person.