Mettā: Loving-kindness
Mettā is the wish for every being to be safe and well. "Love ye your enemies" marks the hardest place to send that wish, and so the place it proves itself. Turn goodwill toward the one who wronged you the way a fire gives its warmth to anyone who steps close and never asks who they are. This is a wish you can choose to send even on a day the warm feeling never arrives.
Cāga: Open-handed giving
Cāga is the open hand that gives and lets go. "Lend, hoping for nothing again" quietly turns a loan into a gift, because once you drop the hope of getting it back there is nothing left to collect. Ordinary lending keeps one eye on the ledger; an open hand closes the book and walks away.
Puñña: Merit
Puñña is the good that a kind act stores up for the one who does it. Here is the paradox of "hoping for nothing again, and your reward shall be great": a gift handed over with a string attached only ever pulls back the small thing tied to that string. Cut the string, and what can return has no ceiling, so the surest road to a great reward is to quit reaching for one.
Upekkhā: Equanimity
Upekkhā is the even mind that offers the same goodwill to everyone. "He is kind unto the unthankful and to the evil" points to a warmth that has stopped dividing people into those who earned it and those who did not. Let your care fall like sunlight that reaches the grateful neighbor and the sour one in the same hour, steady whether or not a thank-you comes back.
Brahmavihāra: The divine abidings
Brahmavihāra means the dwelling of Brahmā, the home of the Most High. "Ye shall be the children of the Highest" lands right here: whoever pours out love without limit comes to live where Brahmā lives and grows into that likeness. A child takes after a parent, and a heart that loves its enemies and gives freely is already moving toward that house.