Is to ignore Satan also to underestimate the potential he has to assault the Christian? I've often thought that, once indwelt by the Holy Spirit and saved by the grace of God, Satan has nothing against me.

But, is to ignore Satan also to underestimate the potential he has to assault the Christian? What do the apostles and disciples of Christ say with respect to Satan's ability against the Christian?
If we could ignore Satan knowing he has nothing against us, we wouldn't need to pay any attention to the scriptures that say


  Be sober, be vigilant; because your adversary the devil walks about
  like a roaring lion, seeking whom he may devour. 1Pe 5:8
  
  The night is far spent, the day is at hand. Therefore let us cast off
  the works of darkness, and let us put on the armor of light. Rom 13:12
  
  Resist the devil and he will flee from you. Jam 4:7
  
  above all, taking the shield of faith with which you will be able to
  quench all the fiery darts of the wicked one. Eph 6:16


All these verses suggest that Satan's threats are as real as his potential for harm. Our fight against the enemy does not end until he is cast into darkness with Death (Rev 20:14).