1 Corinthians 15:10
But by the grace of God I am what I am; and his grace which was bestowed upon me was not in vain, but I labored more abundantly than they all; yet not I, but the grace of God which was with me.
1 Corinthians 15:58
Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, since ye know that your labor is not in vain in the Lord.
Galatians 6:9
And let us not be fainthearted in welldoing; for in due season we shall reap, if we faint not.
Colossians 1:29
to which end I also am laboring, striving earnestly through his working, which worketh within me mightily.