I recently used the first part of 1 Samuel 16:14 in a message about the ebb and flow of the Spirit in people in the Old Testament. It shows that God even sometimes removed the Spirit. Someone later asked about the ending of that verse:

“Now the Spirit of the Lord had departed from Saul, and an evil spirit from the Lord tormented him.”

Does God really send evil spirits to torment and trouble people? It’s a good question.

I did some reading up on that this week, and find most explanations go toward God “giving permission” for an evil spirit to replace his Holy Spirit. So this would be somewhat like the arrangement between God and Satan in the account of Job. Some commentators simply say that if you do not allow the Holy Spirit, it is normal for some other spirit to replace it.

You can read some for yourself on this page, although these are rather old Commentaries that have a bent toward Judgement language rather than consequence language: http://biblehub.com/commentaries/1_samuel/16-14.htm

My own view would be that if you are given a gift of the Holy Spirit, an anointing/calling for a particular special purpose in God’s Kingdom, you risk serious consequences if you do not respect and honour that Spiritual gift. Samson lost it for a time, and Saul lost it. Both for reasons of not respecting it enough. In Saul’s case God (or God’s creation order) allowed for something spiritually darker to come into it’s place. Note that it was ‘for a time’ and did not stay that way.

‘Here’s another place the question is addressed that is helpful, though not exactly in line with my view: http://www.gotquestions.org/evil-spirit-Saul.html