Kansa informed by Nārada of the existence of Krishna and Balarāma; he sends Kesin to destroy them and Akrura to bring them to Mathura - Verse 19
Vishnu Purana (GRETIL; M. M. Pathak critical edition) · 4 · Verse 15.19
Sanskrit Original
जातेन च तेनाखिलम एवैतत सन्मार्गवर्ति जगद अक्रियत। भगवतो ऽप्य अत्र मर्त्यलोके ऽवतीर्णस्य षोडशसहस्राण्य एकोत्तरशताधिकानि भार्याणाम अभवन। तासां च रुक्मिणीसत्यभामाजाम्बवतीचारुहासिनीप्रमुखा ह्य अष्टौ पत्न्यः प्रधाना। तासु चाष्टायुतानि लक्षं च पुत्राणां भगवान अखिलमूर्तिर अनादिमान अजनयत।।
jātena ca tenākhilam evaitat sanmārgavarti jagad akriyata| bhagavato 'py atra martyaloke 'vatīrṇasya ṣoḍaśasahasrāṇy ekottaraśatādhikāni bhāryāṇām abhavan| tāsāṃ ca rukmiṇīsatyabhāmājāmbavatīcāruhāsinīpramukhā hy aṣṭau patnyaḥ pradhānā| tāsu cāṣṭāyutāni lakṣaṃ ca putrāṇāṃ bhagavān akhilamūrtir anādimān ajanayat||
From that birth, the entire world followed the righteous path. In this mortal realm, the Lord descended with more than sixteen thousand one hundred and eight wives, among whom Rukmini, Satyabhama, Jambavati, and Charuhasini were the foremost. He also begot eighty million sons.