Commitment
Commitment enables others to make assumptions about our future conduct that would not be possible without this modality. The unobviousness of this is often overlooked, and it is supposed that a promise is merely a prediction or an expressed intention. Speech-Act theorists analyse performatives accurately up to a point but fail to ask how it is possible that a statement could create an obligation; the answer is that God has created this modality.
"Epangelic" is from Greek epangel (promise). It has no connection with angelic or evangelic.
The old "liege" relationship was asymmetrical, but I use the word with no such implication.
Dooyeweerd's ethical-moral modality conflates commitment with altruism.
Commitment refines animal behaviour into family.
The raising of (animal) mating bonding to the (human) cultural union that is marriage (and of animal family to human initiatory government) is an epangelic phenomenon in which instinctive bonds are affirmed and confirmed.