I guess I see it a little differently. We can only interact with the world from the position of the self. We are all basically selfish and we all want the best for ourselves. What I see as being called to, is to overcoming that basically selfishness that we are born with.
It is about being prepared to sacrifice time, material things, and even personal security for the benefit of others. I used the example of Jean Vanier who came from a family of wealth and privilege to work with mentally disabled people all over the world. The trouble is I then look at myself who is able to take luxurious vacations while millions of people do not have enough to eat.
With very few exceptions we are all selfish. However we can still have hearts that genuinely care and even hurt when we see the suffering of others. We can at least go part way in helping others who suffer and are in need. We are capable, even though still fundamentally selfish, able to perform small or even large acts of born out of a sense that is altruistic.
I would add however that we can also perform what has the appearance of an altruistic act, but is really born out of selfishness. If it is an act to gain the praise of others, or if we are doing it to gain favour with a deity, then it is no longer altruistic, which however does not negate the good that it might do.
He has told you, O man, what is good ; And what does the LORD require of you But to do justice, to love kindness, And to walk humbly with your God.
Micah 6:8