It seems many Christians are being deceived that Satan has the power to interfere with any part of a Christians life at will. If he did, would not he have killed us long ago? Let's see what the Word says:
"He who dwells in the shelter of the Most High
will rest in the shadow of the Almighty. I will say of the LORD, “He is my refuge and my fortress,
my God, in whom I trust.”
Surely he will save you from the fowler’s snare
and from the deadly pestilence.
He will cover you with his feathers,
and under his wings you will find refuge;
his faithfulness will be your shield and rampart.
You will not fear the terror of night,
nor the arrow that flies by day,
nor the pestilence that stalks in the darkness,
nor the plague that destroys at midday.
A thousand may fall at your side,
ten thousand at your right hand,
but it will not come near you.
You will only observe with your eyes
and see the punishment of the wicked."
"For he will command his angels concerning you
to guard you in all your ways;
they will lift you up in their hands,
so that you will not strike your foot against a stone.
You will tread upon the lion and the cobra;
you will trample the great lion and the serpent."
Notice the word "serpent," "lion" and "cobra." It's the same words Jesus used when he said "I have given you authority to trample on snakes and scorpions and to overcome all the power of the enemy; nothing will harm you." The "serpent," "lion" and "cobra" represent (I believe) all the power of the enemy.
The Bible is clear, the enemy has no power to touch a hair on our head. The Bible also says "If you do not stand firm in your faith, you will not stand at all."
The Bible does indicate one context however, in which we must fear Satan. It says "Be self-controlled and alert. Your enemy the devil prowls around like a roaring lion looking for someone to devour." The Bible says we should fear Satan if we life a self-control free life lest God "hand [us] over to Satan." (1 Corinthians 5:5)
Nonetheless, as we clearly see from the scripture "I have given you authority to trample on snakes and scorpions and to overcome all the power of the enemy; nothing will harm you," we have nothing to fear if we are living for God because through Jesus we have power over the enemy.
God bless you!
Joel