Brahma is the trustworthy representative of the Supreme Lord. Therefore when he again asked for the treasure of Vedic knowledge, the Lord fulfilled his desire
SB Canto 5
At the end of the millennium, ignorance personified assumed the form of a demon, stole all the Vedas and took them down to the planet of Rasātala. The Supreme Lord, however, in His form of Hayagrīva retrieved the Vedas and returned them to Lord Brahmā when he begged for them. I offer my respectful obeisances unto the Supreme Lord, whose determination never fails.
Although Vedic knowledge is imperishable, within this material world it is sometimes manifest and sometimes not. When the people of this material world become too absorbed in ignorance, the Vedic knowledge disappears. Lord Hayagrīva or Lord Matsya, however, always protects the Vedic knowledge, and in due course of time it is again distributed through the medium of Lord Brahmā. Brahmā is the trustworthy representative of the Supreme Lord. Therefore when he again asked for the treasure of Vedic knowledge, the Lord fulfilled his desire.