Question: Do two nerves make a right?

Earlier this week we had a team from our ministry go to downtown LA for 4 days to serve and minister in the inner city. Kind of a local missions trip.
We had two of our leaders go with the lead of this trip; for encouragement, support and help.

These are two amazing people whom I feel are completely guided by the Spirit. They are the kind of people whom I feel try their best to carry out God's will in their lives. In no way, shape or form do they live their lives in a selfish way.

Here is where I place my thoughts.

Before going to this trip these two leaders demonstrated a bit of apprehension to going on this trip. They weren't sure if that is where God wanted them to be during this week. Financial burdens presented themselves and they felt like they were going more because of the commitment they had made than because they truly wanted to go. They were nervous...or maybe scared...or maybe God really didn't want them to go.

Question: Do two nerves make a right?
Where is that fine line between feeling fleshly nervousness and feeling uneasiness in your spirit?

How do you know if what you are feeling is coming from your flesh or your spirit?
I know that prayer is the best way to confirm that...but still...these two leaders, I know, will return blessed from their trip, but was it really in God's will for them to go or were their nerves just their flesh guiding them?

Just something I've always wondered...