Metamorphoses Book 6: Niobe
Niobe was a wealthy woman of Thebes, mother of seven sons and seven daughters. In that respect, she counted herself as greater than Latona, mother of Apollo and Diana, because the goddess had only two children. Niobe said, "'I'm too great to suffer Fortune's blows; / Much she may take, yet more than much she'll leave. / My blessings banish fear.'" Book 6 -- Niobe, line 91-3
In anger over the mortal woman's presumption, Latona sent Apollo and Diana to kill her seven sons. Niobe's husband committed suicide in his grief. Niobe still boasted of her greater motherhood because she had seven children left. Latona took care of that and finished off the other seven before she turned Niobe to stone and used a whirlwind to place the statue on a nearby mountain.
In the same vein of warning against scorning the gods, the next two stories were told.