Why does Lame Deer say that the pipe is like an open Bible to him and his people?

The first white man that Lame Deer ever met was very hairy and couldn't ride a horse very well according to Lame Deer. He had eyes of a blue-green color, two .45 Colt guns on his hips, and was chewing tobacco while smoking a cigar. The man spoke in English and tried to trade money for Lame Deer's grandmother's moccasins.