Benjamin continues to explain the reason his people are particularly under the potential penalty of damnation should they follow the evil spirit. The first requirement is that they should know the commandments of God, and he lays before them the evidence that they do. Knowing these things, and then electing to act contrary to them is an election to "withdraw yourselves from the Spirit of the Lord."
It is probably that Benjamin very purposefully uses the phrase "Spirit of the Lord" in this context as a contrast to "evil spirit." He is creating an easily understood polarization between God "the good spirit" and the evil spirit.