Skandapurana 5.244.48

5.244.48

dinasaptakavānbhūtvā tārakaṃ sa haniṣyati ..
iti vākyaṃ tu te śrutvā maṃdaraṃ lokasuṃdaram.. 48 ..

having become seven days old, he will slay Tāraka." / Having heard this speech, [the gods went] to Mandara, beautiful to the world;