It is natural that every king surrounds himself with people of like minds. The same is our God, God is Spirit and he chooses, as friends, people that see with spiritual sight.
Spiritual sight is one trained to recognise the footpath of God and therefore searches diligently for it- when it discovers it, nothing else matters it swings to action. Understanding of this will help with the understanding of faith. An example of this can be seen in the life of Elisha. Elisha never stopped searching in prayers until he discovered the sign of God’s answer.
In the same vein, Caleb and Joshua went with a Moses’ (spiritual) sight searching diligently for the footpath of God (how the land changed to from a barren land to a fruitful one, how the new Israel nation settings could fit into the landscape etc). This explained why they had a different report- they saw the land but discountenanced the ugly (the giants) as if they were inconspicuous and they reported it like that (in the language of Moses).
Spiritual perception in the physical is about being adamant, magnifying the little things and standing by it, not minding the consequence even if it seems foolish or unrealistic. It does not start when you see, it starts before you see- the question is what you want to see?
In summary, God only understands the language of faith, and he longs to have you as friend. Now you know.