Saying Tehillim With Simcha:
The pasuk in Tehillim (65:14) states: “They shout and they also sing.” The Rebbe of Vilednik zy”a (Sefer Sheeris Yisroel, Likutim) explains that if one wishes to scream in order to annul Divine decrees against Klal Yisroel, he should sing with joy. This is seen from the pasuk in Yeshaya (55:12): “With simcha they will go out.” This indicates that through the power of joy, one can go out from all harsh decrees.