I never thought I would be quoting the Urban Dictionary but it gets to the meaning I think is being conveyed in this verse.
“Slug is the ultimate epitome of laziness. A state of idleness and inactivity, primary caused by excessive weed or alcohol consumption.”We tend to think that being lazy is a little thing. The Bible and the thinking of the church do not agree. Sloth is one of the seven deadly sins. It is at the core of the wasted lives we see in our inner cities. I think one of the dangers is that we can grow into it. As children we were quite willing to let someone else pick up after us. If we are not taught to be responsible that can lead to a life expecting servants and for most of us it isn’t going to happen.
So? Be alert to losing your alertness. Don’t let sloth creep up on you.