Ecclesiastes 3:10
I have seen the task which God has given to the sons of men to be humbled by it.
Genesis 3:19
In the sweat of your face you shall eat bread until you return to the ground, for out of it you were taken. For dust you are, and to dust you shall return.
Ecclesiastes 2:26
For God gives wisdom, and knowledge, and joy to a man who is good in His sight. But to the sinner He gives labor, to gather and to heap up, that he may give to him who is good before God. This also is vanity and vexation of spirit.
Ecclesiastes 1:13-14
And I gave my heart to seek and search out by wisdom concerning all which is done under the heavens. It is a sad task God has given to the sons of men to be humbled by it.
1 Thessalonians 2:9
For, brothers, you remember our labor and toil. For laboring night and day in order not to put a burden on any one of you, we preached the gospel of God to you.
2 Thessalonians 3:8
neither did we eat any man's bread freely, but we worked with labor and travail night and day, so that we might not be heavy on any of you