1 Corinthians 15:14, 58
1 Corinthians 15:14 KJV
and if Christ be not risen, then is our preaching vain, and your faith is also vain.
1 Corinthians 15:58 KJV
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.