New Living Translation
So, my dear brothers and sisters, be strong and immovable. Always work enthusiastically for the Lord, for you know that nothing you do for the Lord is ever useless.
English Standard Version
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.
New International Version
Therefore, my dear brothers, stand firm. Let nothing move you. Always give yourselves fully to the work of the Lord, because you know that your labor in the Lord is not in vain.
With all this going for us, my dear, dear friends, stand your ground. And don’t hold back. Throw yourselves into the work of the Master, confident that nothing you do for him is a waste of time or effort.
steadfast (seated, firmly planted) and immovable (no motion); abounding in work (strenuous toil); work is not in vain (not empty or hollow, aimless or purposeless).
“So my dear loving family, be firmly planted with unwavering determination to not quit sweating in work and striving in toil for the Lord Jesus, because our hard work is not empty or without significance but has great purpose for eternity.”