Isvarah paramah krsnah: (BS 5.1) the supreme controller is Krsna. Krsna is never controlled by anyone, for He is the controller of everyone - sarva-karana-karanam

Expressions researched:
"Īśvaraḥ paramaḥ kṛṣṇaḥ: (BS 5.1) the supreme controller is Kṛṣṇa. Kṛṣṇa is never controlled by anyone, for He is the controller of everyone (sarva-kāraṇa-kāraṇam)"

Srimad-Bhagavatam

SB Canto 8

By a scrutinizing analysis, we find that everyone is controlled by something else. No one, therefore, can be the true controller but the Supreme Personality of Godhead, Kṛṣṇa. This is supported by the śāstras. Īśvaraḥ paramaḥ kṛṣṇaḥ: (BS 5.1) the supreme controller is Kṛṣṇa. Kṛṣṇa is never controlled by anyone, for He is the controller of everyone (sarva-kāraṇa-kāraṇam).

SB 8.8.20, Translation and Purport

The goddess of fortune, examining the assembly, thought in this way: Someone who has undergone great austerity has not yet conquered anger. Someone possesses knowledge, but he has not conquered material desires. Someone is a very great personality, but he cannot conquer lusty desires. Even a great personality depends on something else. How, then, can he be the supreme controller?

Here is an attempt to find the supreme controller, or īśvara. Everyone may be accepted as an īśvara, or controller, but still such controllers are controlled by others. For example, one may have undergone severe austerities but still be under the control of anger. By a scrutinizing analysis, we find that everyone is controlled by something else. No one, therefore, can be the true controller but the Supreme Personality of Godhead, Kṛṣṇa. This is supported by the śāstras. Īśvaraḥ paramaḥ kṛṣṇaḥ: (BS 5.1) the supreme controller is Kṛṣṇa. Kṛṣṇa is never controlled by anyone, for He is the controller of everyone (sarva-kāraṇa-kāraṇam).