The Bible gives great importance to the heart. We know the verse which urges us to guard our heart with all diligence. Some other versions of the Bible mention it as, watch over our hearts with all care, utmost care.

All this points to the great importance of keeping a check on what we think and consider and allow our minds to have thoughts about and continue thinking about. Not the word all diligence, all care, utmost care. Essentially pointing that absolutely nothing should be allowed to cross this gate/checkpoint without your intentional approval. Nothing approved should be allowed in. Not to be casual about matters brought for thinking for a moment or longer. The moment you sense it as an unhealthy thought, just change that thought, better still go into a thought acceptable by God. You just do not want to even have a trace of poison thought. Every thought is either healthy or poisonous. Poisons are of various grades – those that induce sudden death or slow death – both are to be hated and not considered.