We have observed that, in society and the world in which we live, selfishness has increased more than love for others, and that men of good will must work, each with his own strengths and expertise, to ensure that love for others increases until it is equal and possibly exceeds love for oneself.

This quote is saying that in the world we live in today, we have noticed that people are becoming more selfish, caring more about themselves than for others. It suggests that people of good will (people who are generous and kind) should work together to make sure that people start caring more for each other than themselves. Using the strengths and expertise they have, they should make sure that kind deeds outnumber selfishness in the world.