Parable of the Arrow

A man approached the blessed one and wanted all his philosopical
questions answered before he would practice.

In response, the buddha said, "It is as if a man had been wounded
by a poison arrow, and when attened a physician said, 'I will not
allow you to remove this arrow until I have leard the caste, age, birth
place, the occupation, and the motivation of the man who wounded
me.' That man would die before haveing learned all this. In exactly
the same way, anyone who should say, 'I wll not follow the teachings
of the Blessed One until the Blessed One has explaind all the multiform
truths of the world - that person would die before the Buddha has
explained all this.

adapted from the Majjhima Nikaya