Because he (Prthu Maharaja) had just been coronated he could not manifest his godly qualities in action. Therefore he was not willing to accept the praise of the devotees

Expressions researched:
"Because he had just been coronated, however, he could not manifest his godly qualities in action. Therefore he was not willing to accept the praise of the devotees"

Srimad-Bhagavatam

SB Canto 4

Pṛthu Mahārāja was an incarnation of the Supreme Personality of Godhead, as Lord Brahmā and other demigods had already testified when they had presented the King with many heavenly gifts. Because he had just been coronated, however, he could not manifest his godly qualities in action. Therefore he was not willing to accept the praise of the devotees.

SB 4.15.24, Translation and Purport

How could an intelligent man competent enough to possess such exalted qualities allow his followers to praise him if he did not actually have them? Praising a man by saying that if he were educated he might have become a great scholar or great personality is nothing but a process of cheating. A foolish person who agrees to accept such praise does not know that such words simply insult him.

Pṛthu Mahārāja was an incarnation of the Supreme Personality of Godhead, as Lord Brahmā and other demigods had already testified when they had presented the King with many heavenly gifts. Because he had just been coronated, however, he could not manifest his godly qualities in action. Therefore he was not willing to accept the praise of the devotees. So-called incarnations of Godhead should therefore take lessons from the behavior of King Pṛthu. Demons without godly qualities should not accept false praise from their followers.