Human morality is based upon – when it does not consist out of mere words or fine speeches or out of intentions that are never realised – the genuine interest of one person in the other, on the ability to truly see another person.
The human being who can empathise with others will, out of this understanding of other people, display social-moral impulses. One can also state that such a person has attained the moral capacities in this earthly existence in pre-earthly life, accomplished from living together with the gods and keeping the urge, at least in the soul, for such a living together on earth. And this shaping of such a living together, enabling one person to accomplish their earthly tasks together with others, that alone in reality forms the moral life on earth. So, we see that love and the effects of love, morality, is solely the result of what the human being experienced spiritually during pre-earthly life.
Source (German): Rudolf Steiner – GA 219 – Das Verhältnis der Sternenwelt zum Menschen und des Menschen zur Sternenwelt – Dornach, 15 December 1922 (Page 62-63)
Translated by Nesta Carsten-Krüger