Time of Divine Favor

The Rosh HaYeshiva, Rabbi Yitzchok Hutner, of blessed memory, is quoted in his Pachad Yitzchak (in the section on the night of Hoshana Rabbah):

The Jewish people are accustomed to turn to Sefer Tehillim, the Book of Psalms, during times of distress and sorrow. Therefore, people think that prayer and the saying of Tehillim are essentially the same thing. This is not so. Tehillim are zemirot, songs of praise. more than a prayer. The difference between them is that while prayer should be recited at a time of Divine favor, the saying of Tehillim has the power to create a time of Divine favor, an Eit Ratzon. In prayer, the content has to be tailored to the need, while in Tehillim, the saying of any part creates an Eit Ratzon. And when there is a condition of Eit Ratzon, troubles depart.

Source: The Foreword in Tehillim Eit Ratzon, Feldheim Publishers