The righteous rejoice in the Lord. As it says (Song of Songs 4:11), "Your lips drip nectar, my bride; honey and milk are under your tongue." The Holy One, blessed be He, said, "I love to hear your voice. Whether in praise or in joyous exultation, do not withhold your voice." (Exodus 15:14) "For your voice is sweet."
They said before the Holy One, blessed be He, "Jacob rejoices over whom? Not over me." It is joyous to me whether in praise or in joyous exultation. And so it says (Jeremiah 31:6), "Sing aloud with gladness for Jacob."
And it also says (Song of Songs 4:11), "Your lips drip nectar, my bride; honey and milk are under your tongue." Your speech is so sweet, like honey and milk. In your palate (Song of Songs 7:10), "And your palate is like the best wine." In your throat (Psalm 149:6), "May the high praises of God be in their throats."
Everything is rejoicing. The righteous rejoice, as it says, "The righteous rejoice in the Lord." And the wicked rejoice as well. Pharaoh rejoiced when Moses and Aaron came, and he began to say, "The Lord is righteous, and I and my people are wicked."
But the wicked do not rejoice before Him until He brings punishment upon them. But the righteous do rejoice in the Lord, as it says, "The righteous rejoice in the Lord." Here it is written "in the Lord," not "to the Lord." While they were seeing, they immediately sang, as it says (Shemot 15:1), "Then Moses and the Israelites sang this song to the Lord."
And similarly, it says (Vayikra 9:23-24), "Moses and Aaron then went into the Tent of Meeting. When they came out, they blessed the people, and the glory of the Lord appeared to all the people. Fire came out from the presence of the Lord and consumed the burnt offering and the fat portions on the altar. And when all the people saw it, they shouted for joy and fell facedown."
And likewise, it says (Divrei Hayamim 2:7:3), "When all the Israelites saw the fire coming down and the glory of the Lord above the temple, they knelt on the pavement with their faces to the ground, and they worshiped and gave thanks to the Lord, saying, 'He is good; his love endures forever.'" Therefore, David said, "Sing to the Lord, you who are righteous; it is fitting for the upright to praise him" (Tehillim 33:1).
Everything sings before Him, the heavens and the earth, the sun and the moon, and the stars of light. The angels also sing, as it says (Tehillim 103:20), "Praise the Lord, you his angels." Although everything sings before Him, the singing of the righteous and the upright is more pleasing than anything else, as it says (Tehillim 33:1), "Sing joyfully to the Lord, you righteous; it is fitting for the upright to praise him."
Give thanks to the Lord with the harp; make music to him on the ten-stringed lyre. Sing to him a new song; play skillfully, and shout for joy (Tehillim 33:2-3). This is for the One who made something new, who laid the heavens and established the earth, as it says (Shemot 25:8), "And let them make me a sanctuary."