But we prayed to our God and posted a guard day and night to meet this threat. (Ne 4:9)
Ecclesiastes says that the man of God will avoid all extremes (Ecc 7:18) This does not mean that we will not be "all out" in our love devotion and commitment to God, his people and his mission, but that where there are two aspects of truth, we will not (or rather we should not) hold fast to one at the expense of letting go of the other.
There are two of these extremes to be avoided when it comes to things practical and things spiritual, if indeed they can be considered to be separate, but indulge me for the sake of a clear explanation. When we are faced with a need, how do we react, spiritually, practically or like Nehemiah — both? One extreme would be to live purely by the natural, with no exercise of faith, meeting practical needs purely with practical responses; but the other extreme is to become "super spiritual" and assume that God must always answer super-naturally to every need.
Those who fall into the first extreme, live by sight and not by faith. They are shaken by every challenge that comes their way if they do not naturally have the resources to meet it. They look at their salary as the limits of their financial resources, without recognising that God is their source. They pop paracetemol as soon as they get a headache without ever considering to pray about it.
Those who fall into the second extreme, live under the delusion that they are being spiritual. They are quick to bring their requests to God, but painfully slow to recognise his answers unless they come in a dramatic way. They will constantly ask God to meet their financial needs, whilst never budgeting or honouring God by seeking to be good stewards of what he has already given. They will storm the heavens at the first sign of a cold, but never consider the Lemsip in the cupboard might be part of God's provision.
I guess at times we have all veered towards one or other of these extremes. What I like about Nehemiah's response is that he does not create any false dichotomy between meeting the threat spiritually and meeting it practically. He does both. It's not a question of should I be spiritual or practical, but "What is the right thing to do?" When he was threatened, he prayed to God and posted a guard.
You could transfer this approach to many areas. If you are in financial need: look to God, and examine your budget. If you have a headache: pray for healing and take a paracetemol. The two are not contradictory. We do not believe like the first century gnostics, that things spiritual are inherently better than things natural. God made both, and he made them well. But nor are we limited like those who have no faith to living purely by the natural. We lift our eyes to see the realities of heaven, and live by what we see there.
"Keep your faith in God, but keep your powder dry" — Oliver Cromwell