The Gemara (Avoda Zara 9a) says that the world will exist is for six thousand years. The first two thousand were empty before the Torah was given, the second two thousand are for Torah, and the last two thousand arefor Moshiach. The Gemara then says that Moshiach should have come, but we are wasting time because of our aveiros.
When did these two thousand years begin? They began 172 years after the Churban Bais HaMikdash. Rav Chaim Kanievsky says that we see a remez for this in Parshas Eikev. “Vehaya eikeiv tishmi’um.” The letters of Eikev have the numerical value of 172. The Torah tells us that if we listen to the Torah and do the mitzvos, all of Hashem’s goodness will be bestowed upon us 172 years after theChurban.