I am going to make an observation as a mission leader that some may take exception to but which I believe to be true: In general missionaries from the west have much different expectations of the Holy Spirit in the missions endeavor than those we serve in the majority world.
It saddens me that many missionaries I meet have very low expectations of what God might actually do through their work. They work hard, expect little and often see little fruit. Often, the very people they work with (from the south and the east) have a much larger expectation of what God intends to do through their ministries. They expect much, and see much fruit.
Why the difference? I believe it has much to do with out view of the Holy Spirit, His work in our lives and our expectation or not that He will show up in a significant way.
In the book of Acts - our best primer on missions there are two concepts that show up together with regularity: proclamation of the Gospel and the power of God. Word and power together. It never surprised Paul with God showed his power in places that the Gospel was proclaimed. It was that power that gave credence to their claims that God was who He was and had the power to change their lives. Miracles, healings, and radical life changes accompanied the proclamation of the Gospel. "In this way the word of the Lord spread widely and grew in power" (Acts 19:20).
Why is it that in the rationalistic west where all things must fit into a neat box and everything have a rationale explanation that we see so little of that power in our ministries? Why is it that in the majority world, that power is regularly seen in miraculous events such as healings that result in people coming to Christ?
The Holy Spirit defies rational explanation. He shows up unexpectedly, and does things that defy explanation. In my own life, in 2007 He chose to miraculously heal my mitral valve when surgery would have been a death sentence because of my dire illness. My cardiologist cannot understand how that happened! So why should I be surprised when God heals regularly in much of the world resulting in people coming to Christ? Or shows up in other amazing ways? Even raising the dead resulting in the birth of churches!
We have been taught too often in the West that all our theology needs to fit into neat little boxes - but God defies fitting into a neat little box. When He chooses to show up in power, the unexpected takes place - we cannot control Him. The real question is whether we in our rationalism are willing to allow Him to show up, expect Him to show up, want Him to show up or believe He will show up.
Expect little and we will see little. Expect that the Gospel is the "power" of God for the salvation of everyone who believes...and pray that God would do beyond what we could "ask or imagine" and He might just do that!
Believers in the majority world don't have the sophistication to know that God is supposed to fit into neat categories. When they read the Scriptures and see God doing the unexpected and miraculous they actually believe he operates that way. When He tells them to ask for much fruit they assume He means what he says. And God blesses them for their naive faith. Actually that naive faith is the faith God wants from each of us.
We have a lot to learn about the power of God through His Spirit. We have a lot to learn about believing that His power breaks through spiritual strongholds and changes hearts. We have a lot to learn about naively believing that He wants to show up in power, surprise us and others and bring people to Him. As for missions from the west, I believe our lack of faith in the power of God, through His Spirit is one of the greatest barriers to seeing the Gospel come the way we see it came in the book of Acts.
What I am encouraged by are the number of workers from the west who are re-examining the role of the Holy Spirit in their lives and ministries. And even reclaiming the "forgotten God" of the Holy Spirit.
Here is my challenge to every Christian. Read the New Testament for the first time! By that I mean, put aside all your theological training, grids and commentaries for a while. Just read the New Testament and ask yourself, "What does the New Testament say about the Holy Spirit and His power in my life?" And, "if what it says is completely true what might I expect Him to do in my life and ministry?" And then - here is the scary part - invite Him to surprise you in your life and ministry. It's an invitation He will not turn down.