Trust in God
Isaiah 54:17
"no weapon forged against you will prevail,
and you will refute every tongue that accuses you.
This is the heritage of the servants of the LORD, and this their vindication from me,"
declares the LORD."
2 Chronicles 20:15-17
"He said: "Listen, King Jehoshaphat and all who live in Judah and Jerusalem! This is what the LORD says to you: 'Do not be afraid or discouraged because of this vast army. For the battle is not yours, bot God's. Tomorrow march down against them. They will be climbing up by the Pass of Ziz, and you will find them at the end of the gorge in the Desert of Jeruel. You will not have to fight this battle. Take up your positions; stand firm and see the deliverance the LORD will give you, Judah and Jerusalem. Do not be afraid; do not be discouraged. Go out to face them tomorrow, and the LORD will be with you.'"
Romans 8:37
"No, in all these things we are more than conquerors through him who loved us."
I John 4:4
"You, dear children, are from God and have overcome them because the one who is in you is greater than the one who is in the world."
Deuteronomy 31:6
"Be strong and courageous. Do not be afraid or terrified because of them, for the LORD your God goes with you; he will never leave you nor forsake you."
Numbers 23:19
"God is not human, that he should lie, not a human being, that he should change his mind. Does he speak and then not act? Does he promise and fulfill?"
You're taking verses out of context and applying to Christians what God said to Israel. For example:
(Isaiah 54:11-17 NIV) "O afflicted city, lashed by storms and not comforted, I will build you with stones of turquoise, your foundations with sapphires. {12} I will make your battlements of rubies, your gates of sparkling jewels, and all your walls of precious stones. {13} All your sons will be taught by the LORD, and great will be your children's peace. {14} In righteousness you will be established: Tyranny will be far from you; you will have nothing to fear. Terror will be far removed; it will not come near you. {15} If anyone does attack you, it will not be my doing; whoever attacks you will surrender to you. {16} "See, it is I who created the blacksmith who fans the coals into flame and forges a weapon fit for its work. And it is I who have created the destroyer to work havoc; {17} no weapon forged against you will prevail, and you will refute every tongue that accuses you. This is the heritage of the servants of the LORD, and this is their vindication from me," declares the LORD.
(Isaiah 55:1-5 NIV) "Come, all you who are thirsty, come to the waters; and you who have no money, come, buy and eat! Come, buy wine and milk without money and without cost. {2} Why spend money on what is not bread, and your labor on what does not satisfy? Listen, listen to me, and eat what is good, and your soul will delight in the richest of fare. {3} Give ear and come to me; hear me, that your soul may live. I will make an everlasting covenant with you, my faithful love promised to David. {4} See, I have made him a witness to the peoples, a leader and commander of the peoples. {5} Surely you will summon nations you know not, and nations that do not know you will hasten to you, because of the LORD your God, the Holy One of Israel, for he has endowed you with splendor."