SB 10.10.7
tau drstva madira-mattau
sri-madandhau suratmajau
tayor anugraharthaya
sapam dasyann idam jagau
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Seeing the two sons of the demigods naked and intoxicated by opulence and false prestige, Devarsi Narada, in order to show them special mercy, desired to give them a special curse. Thus he spoke as follows.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Although in the beginning Narada Muni appeared very angry and cursed them, at the end the two demigods Nalakuvara and Manigriva were able to see the Supreme Personality of Godhead, Krsna, face to face. Thus the curse was ultimately auspicious and brilliant. One has to judge what kind of curse Narada placed upon them. Srila Visvanatha Cakravarti Thakura gives herein a good example. When a father finds his child deeply asleep but the child has to take some medicine to cure some disease, the father pinches the child so that the child will get up and take the medicine. In a similar way, Narada Muni cursed Nalakuvara and Manigriva in order to cure their disease of material blindness.