Incredible vort on Megilas Rus.
The Alshich Hakadosh brings that Machlon was zoche that through the "yibum" of Boaz, Machlon's neshama came back in Oved - the grandfather of Dovid Hamelech. And his almanah Rus produced malchus. What zchus did he have? And why not his brother Chilyon - who was "zoche" that his almanah Orpah produced Golyas?!
Explains the Alshich that Machlon initially was omed b'nisayon and did not marry from the bnos moav. However, Chilyon married Orpah right away. Only afterwards did Machlon "cave in." That is hinted to in the words "v'shem ha-sheini Rus." In the zchus of his restraint, albeit temporary, he was zoche to nitzchiyus. We must learn from this that even if chas v'shalom we fall or slip, every moment of restraint is worth much more than we can imagine!