Achieve Rebirth in the Pure Land

The following passage explains how sentient beings burdened with heavy karma may, nevertheless, achieve rebirth in the Pure Land:

There is a parable in the Questions of King Milinda Sutra:

"A minute grain of sand, dropped on the surface of the water, will sink immediately. On the other hand, a block of stone, however large and heavy, can easily be moved from place to place by boat. The same is true of the Pure Land practitioner. However light his karma may be, of he is not rescued by Amitabha Buddha, he must revolve in the cycle of birth and death. With the help of the Buddha, his karma, however heavy, will not prevent his rebirth in the Pure Land." (Master Thich Thien Tam, Buddhism of Wisdom and Faith, sect. 68 A.)