And let us not grow weary while doing good, for in due season we shall reap if we do not lose heart. (Galatians 6:9)

But as for you, brethren, do not grow weary in doing good. (2 Thessalonians 3:13)

Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, knowing that your labor is not in vain in the Lord. (1 Corinthians 15:58)

For consider Him who endured such hostility from sinners against Himself, lest you become weary and discouraged in your souls. (Hebrews 12:3)

Come to Me, all you who labor and are heavy laden, and I will give you rest. Take My yoke upon you and learn from Me, for I am gentle and lowly in heart, and you will find rest for your souls. For My yoke is easy and My burden is light. (Matthew 11:28-30)