Halakhah su Salmi 100:2

It is written, “Serve the Lord with gladness” (Ps. 100:2)¹Berakoth 31a. and “Serve the Lord with fear” (Ps. 2:11), but how so? ²The Midrash on Psalms, trans. William Braude (2 Vols.; New Haven, Conn.: Yale University Press, 1959), II, 147.(both fear and gladness?) If a man is over-joyful, let him recall the day of death,³Berakoth 31a. this is fear. If he is sad, let him rejoice his heart with matters of the Law,⁴Shabbath 30b. as it is written, “The precepts of the Lord are right rejoicing the heart” (Ps. 19:9).