God told Joshua to "'cross this Jordan . . . to the land which I am giving . . . to the sons of Israel'" (Jos 1:2). God said "'no man will be able to stand before you'" (:5) because "'the Lord your God is with you wherever you go'" (:9). He commanded "'be strong and courageous! Do not tremble or be dismayed'" (:9). He promised "'I will not fail you or forsake you'" (:5). But he warned "'be careful to do according to all the law . . .that you may have success'" (:7).
To be courageous you "let your heart take courage" (Ps 31:24). You believe in and focus on God's promises. "The steadfast of mind You will keep in perfect peace, because he trusts in You" (Isa 26:3). Jesus, himself, was resolute because he said "the Lord God helps Me . . . therefore, I have set My face like flint" (Isa 50:7). Courage means to make your heart firm. You hold firm to your goal when circumstances try to dissuade you. You will have to persevere to prevail. Encourage yourself by cultivating your faith so it develops. A tiny mustard seed grows into a tree (Mt 13:32). Be assured that "for all who are being led by the Spirit of God, these are the sons of God" (Ro 8:14). "For such is God, our God forever and ever; He will guide us until death" (Ps 48:14).
If you need help you have the assurance of Psalm 91:15. "'He will call upon Me, and I will answer him; I will be with him in trouble; I will rescue him, and honor him.'" It is more than God just coming to the rescue. "'With a long life I will satisfy him, and let him behold My salvation'" (:16). "'You created all things, and because of Your will they existed, and were created'" (Rev 4:11).