Shavua Tov. Rabbi Soloveitchik points out that a great deal can be learned from the behavior of Tamar, who ultimately became one of the mothers of the Mashiach.
Tamar was considered a בת כהן, as she descended from Shem, who was considered a Kohein. She realized that it was important for her to connect with the Tribe of Yehuda. She knew that kings would descend from that tribe.
Although she suffered disappointments with the deaths of her first two husbands, ער and אונן, and she was not given to the third son, שלה, she did not give up. She waited and persevered.
This was the lesson Tamar taught us. When you believe in something and know it is truth, persevere. Your convictions may be questioned, but you must not waver. The truth wins in the end.
Even in business, I once read that the biggest reason why some businesses fail, is that people give up too soon. If they would have had a little more patience, they would have succeeded. We have to stop expecting instant results.
Tamar did not give up and kings and Mashiach will have descended from her.