Built on Kindness.
Ki Tetzei (Deuteronomy 21:10-25:19 )
"An Ammonite or a Moabite shall not enter into the congregation of God, even to their tenth generation… because they didn't greet you with bread and water when you left Egypt" (Deut. 23:4). It is interesting that, despite the fact that the Torah exhorts us countless times to be sensitive to a convert and welcome him with open arms, there are two nations that are eternally banned from marrying a Jew, even if they would convert.
Not the Egyptians, who enslaved us, but the nations of Ammon and Mo'ab. They possessed a spiritual defect that is not only the antithesis of what it means to be a Jew, but the antithesis of what it means to be human. The Torah condemns them because when the Jewish nation was passing through their land on the way to Israel, they refused to give them bread and water. Ammon even refused to sell it to them.
The Torah seems to understand that indifference, callousness, and a complete lack of compassion will engender the end of humanity. The world exists only because of kindness emanating from God, and to the extent that we can let go of our egos and resist the temptation to be indifferent towards others, our connection with God will develop exponentially.
King David says it all when he writes, "The world is built on kindness," meaning that our entire existence, both individually and universally, depends on it.
(Based on the teachings of Rav Nebenzahl.)