I interpret this as an anti-drug song, specifically anti-heroin. Heroin is commonly referred to as "horse" in drug circles. "You can not see the hole in front of you" - you think you can handle the drug but you soon find that you've slipped down the rabbit hole of addiction. "If you take, then step aside" - if you abuse your body with this poison, be ready to suffer the consequences.
I interpret this as an anti-drug song, specifically anti-heroin. Heroin is commonly referred to as "horse" in drug circles. "You can not see the hole in front of you" - you think you can handle the drug but you soon find that you've slipped down the rabbit hole of addiction. "If you take, then step aside" - if you abuse your body with this poison, be ready to suffer the consequences.