If you're an ISTP, you probably want to know how something works before you commit to it, and you'd rather do a thing than discuss it. Neither of those is a problem for following Jesus. The Bible has a whole chapter about a man who asked God for evidence twice and got it.
God Called Gideon in a Winepress
Here's the situation. Israel is being raided by the Midianites, who take the harvest every year, so Gideon is threshing wheat down inside a winepress to hide it. A winepress is the wrong place to thresh wheat. You thresh on an open floor where the wind can carry the chaff off. He's doing it in a pit because he's trying not to get robbed, which tells you everything about the state of the country.
That's where the angel of the Lord finds him. "The Lord is with you, mighty warrior" (Judges 6:12).
And Gideon does not say amen. He argues. "Pardon me, my lord, but if the Lord is with us, why has all this happened to us? Where are all his wonders that our ancestors told us about?" (Judges 6:13). Then when God tells him to go save Israel, he pushes back a second time: "how can I save Israel? My clan is the weakest in Manasseh, and I am the least in my family" (Judges 6:15).
Two objections, both practical, neither of them spiritual. He wants to know how the numbers work. God's answer is not a lecture. It's "I will be with you" (Judges 6:16), and then a job.
He Asked for Proof and Got It
Gideon still isn't sure, so he runs a test. He puts a wool fleece on the threshing floor and asks God to put dew on the fleece and leave the ground dry. God does it, and Gideon wrings out a bowlful of water in the morning.
Then he asks for the same test again, backwards. "Do not be angry with me. Let me make just one more request. Allow me one more test with the fleece, but this time make the fleece dry and let the ground be covered with dew" (Judges 6:39). And God does that too.
He knows he's pushing it. He says so before he asks. God doesn't rebuke him, and he doesn't withdraw the assignment either.
So if you need to see something work before you'll trust it, God has dealt with that before and he wasn't offended by it. Ask him. Be honest that you're asking for proof. What Gideon does not do is use the fleece to get out of the job, and that's the line. Testing God's word so you can act on it is Gideon. Testing it so you can put off acting on it is something else.
Faith That Shows Up as Work
Watch what Gideon's obedience actually looks like once he's convinced. He doesn't write anything down. He pulls down his father's altar to Baal at night, gathers three hundred men, and goes. His faith is a series of physical actions in a specific place.
That's available to you in a way that a devotional habit built entirely out of reading may not be. Fix something at the church. Drive somebody to an appointment. Do the setup and teardown nobody wants. Learn the sound board. Build the ramp. When you serve with your hands you are not doing a lesser version of the spiritual life, you're doing the version the New Testament describes most often.
The trap on this side is using the work to avoid the people. Fixing the building is easier than sitting in a group and saying how you're actually doing. Do both, and let somebody find out what's going on with you.
The other thing worth knowing about how you're built is what happens in a crisis. Most people freeze or start talking. You assess and move. That's a real gift to a church, and it shows up at the worst moments: the medical emergency in the lobby, the family that has to move out in three days, the friend whose car died the week rent is due. You'll see the next practical step before anybody else in the room does, and you'll take it without being asked. Don't file that under "not spiritual" because it doesn't feel like prayer. Somebody in that moment is experiencing the care of God through a person who knew what to do, and that person is you.
Who Else Wanted to See It First
The Bible never labels anybody with four letters, so this is a pattern rather than a list of ISTPs. The pattern is easy to spot.
Gideon wants to know how it's going to work, and tests it twice. Thomas says he won't believe until he puts his hand in the wounds, and Jesus shows up and lets him. Bezalel gets filled with the Spirit of God specifically to work in gold, stone, and wood. Peter, in the crisis, doesn't deliberate. He gets out of the boat and he swings the sword.
Where This Goes This Week
Here's where this goes this week. Ask God for something specific, watch for the specific answer the way Gideon did, and write down what happened. Read the narrative books, Judges and Samuel and the Gospels, where things happen instead of getting explained. Take one hands-on serving job and treat it as time with God rather than a chore standing in front of the real thing. And tell one person how you're actually doing, out loud, because the work will not do that for you.
God met Gideon in a pit where he was hiding grain, called him a mighty warrior before he'd done anything, and then answered his questions twice. He can handle yours.