Buddhist Dictionary of Pali Proper Names by G P Malalasekera
Udakūpama Sutta
Udakūpama Sutta:There are seven kinds of people in the world who are like objects that fall into wells:Some having sunk into the water remain there; others continue sinking and rising; some having risen once will not sink again; others having risen will look round,etc.Similarly,some having fallen into sin never escape there from,others are prone to weakness but often check themselves,etc.A.iv.11-13.