It’s my birthday on the Jewish calendar!
Today is a day for mourning with the Jewish people. Pray for peace and safety. Practically speaking, read some or all of the book of Lamentations, skip out on sweets and indulgences, or fast if you are so inclined. Since I have done this now a couple of times, I have learned that one of the ways to learn what true joy is all about is to practice real mourning. Sit on the floor when reading. Try and get a sense for the tragedy and difficulties of exile and dispersion: no unified nation, no land, no Jerusalem, no true joy. I’m so thankful that we are alive to see a new state of Israel and are able to help in whatever way we can.
And there are lots of blog posts you can find from Messianic and Jewish believers about this day. Here is one:
http://www.messianicjudaism.me/musings/2011/08/08/classic-reprint-tisha-bav/