Each Generation's Own Mitzvah
Noach was whole "in his generations" because in every generation he lived through, he held fast to the particular mitzvah that generation needed.
Why does the Torah say Noach was whole "in his generations" and not "in his generation"? The Noam Elimelech answers that Noach lived through several generations, and the plural teaches something more than the familiar debate over whether the words are praise or a measure. Every generation, the Rebbe explains, has at its root one particular mitzvah it is meant to repair more than the others. In his own generation, he writes, it was the mitzvah of tzitzis. Noach was whole in each of his generations because in each one he found the mitzvah at its root and held fast to it. And when a tzaddik fulfills a mitzvah at its root, it sets him burning with warmth and moves him to sing Hashem's praise, as the verse says, "Those who seek Him will praise Hashem; may your hearts live forever."
Source: Noam Elimelech, Bereishis, Noach (on Bereishis 6:9)
Ask yourself which mitzvah your home, your community or this season of your life most needs right now. It might be shalom in the family, honest speech, or simply davening with a minyan. Choose one, and this week give it extra care: do it a little earlier, a little more fully, with a moment of thought before you begin. Notice whether it starts to warm you from the inside. That warmth is a sign you have found its root.