I was in Washington D.C. last week visiting my daughter.  She pointed out that Three Dog Night had a concert scheduled while I was there.  We attended and it was spectacular!!  I know all of us have seen oldies artists who are well-past their time and at-best, were "okay."  Danny Hutton, still lead singer was super except when he had to stretch his voice in a really high octave - he did it but his voice was stretching.  The two and a half hour concert was outstanding with them playing all of the Top 40 songs plus some.  
So, on their second-to-the-last song, Danny gave a brief intro, stating that the song was NOT POLITICALLY motivated, that they simply wanted to pay tribute to the innocent children of school shootings and children who have been victims of world-wide wars.  Song title: Prayer of the Children, written by Kurt Bestor back in the 80s(?).  The ambience was special:  an "intimate" venue (~300 people), lights were all turned out except for lights on all 7 of the performers, a capella for a "mystic, religious" experience.  As they faded at the end of the song, there was dead-silence for about 5 seconds - not a dry eye in the house.  Then there was a spontaneous rising of the audience from their seats as they applauded, screamed and whistled their overwhelming appreciation of the sound.  WOW!!

https://www.youtube.com/watch?v=Y8vRraYKVi4

I later researched the Dog's history:  It's not a new song.  They've been including this song at every one of their performances since they recorded it as single in 2009.  It was supposed to be included in their "Road Ahead" album.  As far as I could research, that album hasn't happened yet.  I have researched many of my resources and could find no copy of this song anywhere for sale.
They ended the concert on an upbeat note with Joy To The World!!