King James Version
Therefore, my beloved brethren, be ye stedfast, unmoveable, always abounding in the work of the Lord, forasmuch as ye know that your labour is not in vain in the Lord.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.Catholic Public Domain Version
And so, my beloved brothers, be steadfast and unmovable, abounding always in the work of the Lord, knowing that your labor is not useless in the Lord