The great sons (Marici and the great sages) began to pray to the Supreme Lord for the good sense of Brahma (Brahma was sexually inclined to his own daughter)

Expressions researched:
"the great sons began to pray to the Supreme Lord for the good sense of Brahma"

SB Canto 3

Lust for sexual intercourse is so strong that it appears herein that Brahmā could not be dissuaded from his determination in spite of the appeal by his great sons like Marīci. Therefore, the great sons began to pray to the Supreme Lord for the good sense of Brahmā.

SB 3.12.32, Translation and Purport:

Let us offer our respectful obeisances unto the Personality of Godhead, who, by His own effulgence, while situated in Himself, has manifested this cosmos. May He also protect religion for all goodness.

Lust for sexual intercourse is so strong that it appears herein that Brahmā could not be dissuaded from his determination in spite of the appeal by his great sons like Marīci. Therefore, the great sons began to pray to the Supreme Lord for the good sense of Brahmā. It is only by the grace of the Supreme Lord that one can be protected from the allurement of lusty material desires. The Lord gives protection to devotees who are always engaged in His transcendental loving service, and by His causeless mercy He forgives the accidental fall of a devotee. Therefore, sages like Marīci prayed for the mercy of the Lord, and their prayer was fruitful.