who through faith are shielded by God's power until the coming of the salvation that is ready to be revealed in the last time.
What are we shielded from?
If you read on in the next few verses, you will see quite plainly that you are not shielded from life's hardships. There are many a Christian who has learned this truth the hard way. After they have chosen to follow God's path, there are many who meet with discouragement because they are still encountering trials and temptations.
When we read of the full armor of God, the shield of faith is used to quench the fiery darts of the devil. Faith is what makes it possible to believe in God's truths, without seeing them. None of us has seen the Father, but without seeing we believe, and we follow His ways.