Paul said, we should not be "ignorant" of Satan's devices. We need to know that the devil and demons exist, and we need to recognize when we are facing demonic activity; but we need to keep our focus on the Lord.
Some people who are excessive in "spiritual warfare" actually spend more time talking to the devil each day than they do talking to God. That's not right.
The best defense against the devil is to be so "God-centered" that we give no place to Satan. People who are very sensitive to the devil's presence usually do so at the expense of being sensitive to the Lord's presence. David said, "If I make my bed in hell, behold, thou art there" (Psalm 139:8). Any time Satan's oppression is there, God's presence is present also (Hebrews 13:5)! It's just a matter of which one we focus on. Focusing on the devil is a trick of the devil.
Our ability in the Christian life is found in Christ. It is not our ability that makes us strong, but our availability to Christ that enables us.
Paul said, "For when I am weak, then am I strong" (2 Corinthians 12:10). He was saying that when he recognized his inability and, relied on the Lord, then the Lord's strength flowed through him. We can do all things THROUGH CHRIST who strengthens us!