1 Peter 5:8 Be sober, be vigilant; because your adversary the devil walks about like a roaring lion, seeking whom he may devour.
When the apostle says to be sober and vigilant, they cannot realistically be done without each other; trying to be vigilant if one is not sober in mind and spirit would be a lost cause.
We have a very real threat, the evil one, who is always out to try and trip us up at every opportunity; just to try and prevent us from being close to God!
When we hear a sound which frightens us, that feeling runs deep inside and not just on the exterior – the devil is out to frighten us as much as possible.
Trust in Christ and depend on Him as your protector at all times.