D&C 63
Verse 15 is a warning to sinners that if they do not repent before their sin is generally known they will be remembered by the people for that sin even after they have repented.
The Lord promises to make some things known not by way of commandment because many do not keep the commandments. By keeping some things as not commandments they will not be a source of condemnation for those who do not keep them, but those who keep the commandments will receive them and keep them and be blessed as they learn the mysteries of the kingdom.
The saints are told to purchase the land of Zion that they might have claim on the world and not stir people up to anger. He says that it can be obtained by blood instead, but that it would lead to them being scourged from city to city.