The deeper the concentration the more equanimous the mind.  Nothing can shake it.  The Buddha said a concentrated mind is a malleable, wieldy and imperturbable mind.
            With stability comes security, inner security. With the development of wisdom and equanimity comes a deep, lasting security from within.  This is not a security that is based on externals, people, places and things, to bring us lasting happiness.  We know, we have discovered, through the practices of anapana sati and mindfulness, once again the true nature of all phenomena, the three marks of conditioned existence, as mentioned above, that there is no lasting security in things which are liable to suffering, constant change and emptiness. 
            Actually, we find great security in knowing the truth of these three marks of conditioned existence!.  We can count on them!
            A stable mind, a concentrated mind, an equanimous mind and heart, filled with wisdom, is not shaken by perceiving the true nature of all phenomena.
            OK! Sounds great.  Sure.  Why not?  But what is it that limits our equanimity?
            When we fight something, resist what is, struggle with a person, place, or thing, our own minds, conflicts in our hearts, our equanimity is compromised at best and is gone in most cases.
            When our self image or identity does not match our actions and behavior or vice versa, our equanimity ceases.
            For example, when my father is in deep physical pain, suffering from sciatica and I want to take all his pain away and am unable, I experience this conflict.  What can't I remove it all?  Oh yes, I can lend a hand, make nutritious meals, massage him twice a day, bring cheer to his spirits, all actions which alleviate suffering. And I can maintain equanimity through it all.  But the minute I, his loving daughter hands-on healer, want to take all his pain,  become involved, identified and attached to that end,  the trouble begins.  I am in a fight, a struggle between my identity and the limits of what I can do. Equanimity is nowhere in sight. Now we have dukkha squared.  Now, there is not only my father's suffering but my own as well. I am no longer part of the solution but part of the problem, which is guaranteed to happen with dukkha squared.  There is a cause and effect relationship! 
            Once I let go of the conflict between my identity, get myself out of the way, surrender to what is, accept both my father's pain and the limits of what I can do, equanimity is restored.  I once again do what needs to be done from a place of balance within myself.
            Mindfulness, awareness, the culmination of hours, years spent on the cushion, applied in a moment, restores equanimity.
            Wake up to the moment! Know what is! As it arises and passes away, perceive the true nature of phenomena.

Remember: The seed of mindfulness planted and cultivated bears the fruit of equanimity.