Why is is to hard for the flesh to walk by faith?
Because the flesh is dying and struggling for survival at any cost. Faith is the essence of eternal investment, and it is the thing to which the flesh is the most opposed.
The two greatest faith struggles are those that concern money and those that concern immediate family members, usually spouses.
Money seems so important. After all, it is the ingredient needed for physical transactions that relate to survival. What does the Bible say? That we should pray in our Daily Bread. That we should look to Him who has promised to meet our every need. That we should give out of our lack. That we should give of the first fruits. That if the sparrow lacks for nothing, neither will we.
Why then is it so hard? Because the flesh wants control.
What about relationships? He says "Seek ye first the Kingdom of God and all these things shall be added unto you." He says that He must be first and that is all there is to it.
Conflicts must be brought to Him in prayer. Faith agrees that He hears and that He cares.
Faith agrees that He intervenes.
Faith agrees He knows better than we.
Faith agrees that while we may not see the result here, we shall see the result in eternity.
Faith agrees that our feeling does not compare with His Plan.
Soldier of The Cross, look beyond the immediate. Gaze upon Him. Consider the Word. The flesh kicks and screams, but the Spirit beckons to living on the Higher Ground.
There is simply nothing else. There is no one else.