discourse-icon is a new theme component which allows you to use icons from your SVG icon subset in a post.

Usage:

[wrap=icon id=square][/wrap]

Example:
This is the [wrap=icon id=far-square][/wrap] icon and the [wrap=icon id=pencil-alt][/wrap] icon.

This is the [wrap=icon id=far-square][/wrap] icon and the [wrap=icon id=pencil-alt][/wrap] icon.

Code:
https://github.com/discourse/discourse-icon

Note: if the icon doesn’t show it’s because it’s not in your subset. If you are admin you can add it in your site settings: svg icon subset.