Add punctuation: In addition to letters which have survived which tell us important facts about his achievements we also have some lectures which he gave
A: In addition to letters which have survived which tell us important facts about his achievements, we also have some lectures which he gave.

Add punctuation: 6 And the tongue is a fire a world of iniquity so is the tongue among our members that it defileth the whole body and setteth on fire the course of nature and it is set on fire of hell
A: 6 And the tongue is a fire, a world of iniquity: so is the tongue among our members, that it defileth the whole body, and setteth on fire the course of nature; and it is set on fire of hell.

Add punctuation: Counted in a census in Sinding Denmark
A:
Counted in a census in Sinding, Denmark