1 Corinthians 15:10
But by God's grace I am what I am; and His grace which was bestowed upon me did not prove 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, become steadfast, immovable, abounding in the work of the Lord, knowing that your labor is not in vain in the Lord.
Galatians 6:9
And, in doing what is noble, let us not grow weary; for in due season we shall reap, if we faint not.
Colossians 1:29
to which end I am toiling also, striving according to His working, which is working in me with power.