PURPORT

When Diti, Indra's aunt, explained to Indra without reservations what she had wanted to do, Indra explained his intentions to her. Thus both of them, instead of being enemies, freely spoke the truth. This is the qualification that results from contact with Visnu. As stated in Srimad-Bhagavatam (5.18.12):

yasyasti bhaktir bhagavaty akincana
sarvair gunais tatra samasate surah

If one develops a devotional attitude and becomes purified by worshiping the Supreme Lord, all the good qualities are certainly manifested in his body. Because of being touched by worship of Visnu, both Diti and Indra were purified.