10 I have seen the travail, which God hath given to the sons of men to be exercised in it.
Ecclesiastes 3:10 Cross References - KJV_Cambridge
Genesis 3:19
19 In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return.
Ecclesiastes 1:13-14
Ecclesiastes 2:26
26 For God giveth to a man that is good in his sight wisdom, and knowledge, and joy: but to the sinner he giveth travail, to gather and to heap up, that he may give to him that is good before God. This also is vanity and vexation of spirit.
1 Thessalonians 2:9
9 For ye remember, brethren, our labour and travail: for labouring night and day, because we would not be chargeable unto any of you, we preached unto you the gospel of God.
2 Thessalonians 3:8
8 Neither did we eat any man's bread for nought; but wrought with labour and travail night and day, that we might not be chargeable to any of you: