We may feel at times that we are at the mercy of the forces of falsehood and evil in the world, and even of our own stresses and fluctuating emotions. It is true that there are certain things that are beyond our control (and it's actually healthy to recognize that), but there's something more we should know before being carried away by the tides of the present times.
"Before I formed you in the womb I knew you, and before you were born I consecrated you..." (Jeremiah 1:5). God knows you, He has always known you, He has always had a plan for your life: "I consecrated you, I appointed you..." (ibid.) This in itself should be enough to convince us that we are not cut adrift, not helpless to fight "the beast," the evils that come from the demons or simply from the malice or ignorance of other people.
But there is more. God not only knows, chooses, and appoints a personal task for us, He gives us strength and protection against all that would hinder or prevent us from carrying out his will. "Do not be dismayed... Behold, I make you this day a fortified city, an iron pillar, and walls of bronze... They will fight against you, but they will not prevail, for I am with you to deliver you, says the Lord" (Jer. 1:17-19).
Our failures often are the result of our ignorance of what God has called and equipped us to do. We look only at our limitations, and not at God's omnipotence. Jeremiah, when he received his mission, complained that he was but a youth and thus incapable of fulfilling it. But God said, "Do not say, 'I am only a youth'; for to all to whom I send you, you shall go, and whatever I command you, you shall speak. Be not afraid of them, for I am with you..." (Jer. 1:7-8).
God is with you. What is it that you fear--other people, temptations, sufferings, spiritual warfare, the vicissitudes of life? Remember, the Lord has made you a fortified city with walls of bronze. He doesn't promise that enemies won't fight you, only that they will not prevail (if you are faithful to Him). Your walls are strong, for they are the work of the Lord. "Fear not, stand firm, and see the salvation of the Lord... The Lord will fight for you" (Exodus 14:13-14).