Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 18

Sanskrit:

न मय्युपैष्यत्यरिबुद्धिमच्युत:कंसस्य दूत: प्रहितोऽपि विश्वद‍ृक् ।योऽन्तर्बहिश्चेतस एतदीहितंक्षेत्रज्ञ ईक्षत्यमलेन चक्षुषा ॥ १८ ॥

ITRANS:

na mayy upaiṣyaty ari-buddhim acyutaḥkaṁsasya dūtaḥ prahito ’pi viśva-dṛkyo ’ntar bahiś cetasa etad īhitaṁkṣetra-jña īkṣaty amalena cakṣuṣā

Translation:

The infallible Lord will not consider me an enemy, even though Kaṁsa has sent me here as his messenger. After all, the omniscient Lord is the actual knower of the field of this material body, and with His perfect vision He witnesses, both externally and internally, all the endeavors of the conditioned soul’s heart.

Purport:

Being omniscient, Lord Kṛṣṇa knew that Akrūra was only externally a friend of Kaṁsa. Internally he was an eternal devotee of Lord Kṛṣṇa.