SB 4.11.12

sa tvaṁ harer anudhyātas
 tat-puṁsām api sammataḥ
kathaṁ tv avadyaṁ kṛtavān
 anuśikṣan satāṁ vratam
Word for word: 
saḥ — that person; tvam — you; hareḥ — by the Supreme Lord; anudhyātaḥ — being always remembered; tat — His; puṁsām — by the devotees; api — also; sammataḥ — esteemed; katham — why; tu — then; avadyam — abominable (act); kṛtavān — you have undertaken; anuśikṣan — setting the example; satām — of saintly persons; vratam — a vow.
Translation: 
Because you are a pure devotee of the Lord, the Lord is always thinking of you, and you are also recognized by all His confidential devotees. Your life is meant for exemplary behavior. I am therefore surprised — why have you undertaken such an abominable task?
Purport: 

Dhruva Mahārāja was a pure devotee and was accustomed to always thinking of the Lord. Reciprocally, the Lord always thinks of those pure devotees who think of Him only, twenty-four hours a day. As a pure devotee does not know anything beyond the Lord, so the Lord does not know anything beyond His pure devotee. Svāyambhuva Manu pointed out this fact to Dhruva Mahārāja: “Not only are you a pure devotee, but you are recognized by all pure devotees of the Lord. You should always act in such an exemplary way that others may learn from you. Under the circumstances, it is surprising that you have killed so many faultless Yakṣas.”