Special Trait of Chessed

Each of the three angels sent by G-d to Avraham Avinu, had a different mission. One was to heal Avraham after his Brit, and save Lot. This was considered one mission.
Another angel was to inform Sara that she was going to have a son, and the third angel was to destroy Sodom.

Rav Kook asked why it was necessary for this third angel to visit Avraham, when his mission was in Sodom, and not in Eilonei Mamre, where Avraham was living.

He answered that it was important for this angel (probably Gavriel) to witness the extent of the Chessed of Avraham. There was no law among the Seven Noachide Laws to give charity or do acts of kindness. Assurances were needed to prove the justification of destroying five cities.

As long as it was seen that a different path of goodness was taken elsewhere, the correct thing to do would be to rid the world of evil.

Rav Kook also mentions that Avraham had not yet acquired the reputation of being a man of Chessed. We get a glimpse of this when we see how he fulfilled the Mitzva of welcoming guests, even when he was recovering from surgery.

This also explains the words of the prophets who said, עולם חסד יבנה, that the world was created for acts of kindness. This serves as a reminder that we, too, are to be actively involved in acts of kindness. It has certainly been most inspiring during this past difficult year to see the way that the entire Jewish people have stepped up to help our brave soldiers and their families.

There is also immediate reward for doing acts of kindness. It brings us great joy to know that we made a difference in easing the plight of those who are suffering.
Avraham Avinu set the example for his descendants of Chessed. This is a character trait that we must cherish.