Luke 18:1
And he told them a parable to the effect that they ought always to pray and not lose heart.
1 Corinthians 15:58
Therefore, my beloved brothers, be steadfast, immovable, always abounding in the work of the Lord, knowing that in the Lord your labor is not in vain.
Ephesians 6:11–12
Put on the whole armor of God, that you may be able to stand against the schemes of the devil. For we do not wrestle against flesh and blood, but…against the spiritual forces of evil in the heavenly places.