Rami, I apologize for not providing a scripture reference for The Loving Father and His Two Sons. I had in mind Luke's account of what we used to call the Parable of the Prodigal Son. If you want to alter your comments in light of this information, have at it!
I especially like the way your interpretation of the beatitude makes room both for the visionary and the doer. In addition, I suspect you may be right in connecting mercy-giving to "Do unto others as you would have them do unto you."
You may be correct. All religions may stress such a teaching. I've never had the resources or time to verify the truism. Like "mercy," we might need to determine the definition of religion in question. For example, if religion is that which brings structure, meaning and direction to life (the broadest definition I can think of, off the cuff), many "isms" and their ilk come into play. The two of us could generate quite a list! For example, I would argue that raw consumerism, capitalism, communism, and the like give short shrift to mercy. In fact, undiluted versions of such "religions" regard mercy as weakness.
Mercy, it turns out, is highly subversive!
The practice of mercy changes us in a number of ways and quickly teaches us our limits. We run out of steam in short order. In my own experience, I find the practice of centering prayer essential to the ongoing practice of mercy. Mercy-giving prompts the development of empathy as well. The more often we grant mercy, the more keenly we come to sense our kinship. All of us fail and hurt others and stand in need of mercy. My hunch is that mercy-giving ultimately engenders the growth of God's kind of love within us, both "hesed" (unbreakable love) and "agape" (self-giving love). In fact, the practice of mercy may be the key spiritual discipline required.