One verse

Srimad Bhagavatam 10.1.64

10.1.64

एतत् कंसाय भगवाञ्छशंसाभ्येत्य नारद: । भूमेर्भारायमाणानां दैत्यानां च वधोद्यमम् ॥ ६४ ॥

etat kaṁsāya bhagavāñ chaśaṁsābhyetya nāradaḥ bhūmer bhārāyamāṇānāṁ daityānāṁ ca vadhodyamam

etat
all these words about the Yadu family and Vṛṣṇi family
kaṁsāya
unto King Kaṁsa
bhagavān
the most powerful representative of the Supreme Personality of Godhead
śaśaṁsa
informed (Kaṁsa, who was in doubt)
abhyetya
after approaching him
nāradaḥ
the great sage Nārada
bhūmeḥ
on the surface of the earth
bhārāyamāṇānām
of those who were a burden
daityānām ca
and of the demons
vadha-udyamam
the endeavor to kill

Once the great saint Nārada approached Kaṁsa and informed him of how the demoniac persons who were a great burden on the earth were going to be killed. Thus Kaṁsa was placed into great fear and doubt.