Keep your heart with all vigilance,
    for from it flow the springs of life.

(Proverbs 4:23)

What does it mean to guard/keep your heart?

Does it mean an external or internal exercise or is a combination of both?

Are we to build a physical or virtual fence around our hearts or are we to inject vaccines into our hearts to build internal immunity or do we build fences and ensure we are up to date on ‘heart’ vaccines as well?

And what exactly are we guarding/keep our hearts against/from?