Lord Siva is the topmost Vaisnava (vaisnavanam yatha sambhuh). It is therefore said, vaisnavera kriya. Even the most intelligent person cannot understand what a Vaisnava like Lord Siva is doing or how he is acting

Expressions researched:
"Lord Śiva is the topmost Vaiṣṇava (vaiṣṇavānāṁ yathā śambhuḥ). It is therefore said, vaiṣṇavera kriyā-mudrā vijñe nā bujhaya. Even the most intelligent person cannot understand what a Vaiṣṇava like Lord Śiva is doing or how he is acting"

Srimad-Bhagavatam

SB Canto 8

Lord Śiva is the topmost Vaiṣṇava (vaiṣṇavānāṁ yathā śambhuḥ). It is therefore said, vaiṣṇavera kriyā-mudrā vijñe nā bujhaya. Even the most intelligent person cannot understand what a Vaiṣṇava like Lord Śiva is doing or how he is acting.

SB 8.7.33, Translation and Purport

Exalted, self-satisfied persons who preach to the entire world think of your lotus feet constantly within their hearts. However, when persons who do not know your austerity see you moving with Umā, they misunderstand you to be lusty, or when they see you wandering in the crematorium they mistakenly think that you are ferocious and envious. Certainly they are shameless. They cannot understand your activities.

Lord Śiva is the topmost Vaiṣṇava (vaiṣṇavānāṁ yathā śambhuḥ). It is therefore said, vaiṣṇavera kriyā-mudrā vijñe nā bujhaya. Even the most intelligent person cannot understand what a Vaiṣṇava like Lord Śiva is doing or how he is acting. Those who are conquered by lusty desires and anger cannot estimate the glories of Lord Śiva, whose position is always transcendental. In all the activities associated with lusty desires, Lord Śiva is an implement of ātma-rāma. Ordinary persons, therefore, should not try to understand Lord Śiva and his activities. One who tries to criticize the activities of Lord Śiva is shameless.