First of all, let me say that there’s nothing encouraging about “grieving the Holy Spirit” as an act in and of itself. We are commanded in Ephesians to not grieve the Holy Spirit through refusing to walk in obedience to the Spirit.
So while there obviously isn’t any encouragement in sinning, there is something encouraging about the language intentionally used by Paul in this passage. To get to that encouragement, think about this question:
Why are we told not to “grieve the Holy Spirit, rather than “anger” the Spirit or something like that?
Here is where we find the encouragement, because “grief” by its very nature is a much more personal emotion than anger.
If someone cuts you off in traffic, you don’t grieve. You get mad. But if one of your children makes a destructive choice, you might indeed be angry, but there is another depth to that anger. There is grief because of what was lost as a result of that choice. Because of your great love for your child, you grieve what might have been but for these choices. You grieve the sense of brokenness in your relationship. It’s anger, sure – but it’s anger motivated by a very deep love and concern.
That’s the part of grieving the Holy Spirit that’s encouraging.
The language here reveals the depth of love God has for us. We don’t just make the Spirit mad when we’re disobedient; we grieve Him because of similar reasons an earthly parent might be grieved.
Here again we are reminded of the tremendous love God has demonstrated for us. He had brought us into His family, refusing to hold us at an arm’s distance. We can rest assured, then, because of the grieving of the Holy Spirit, that God has convincingly and overwhelmingly committed Himself to us in Christ.
Thank God the Spirit grieves and doesn’t just get mad.