1 Thessalonians 2:9

For you remember, brethren, our labor and toil: night and day working, that we should burden no one of you, we preached unto you the gospel of God.

2 Thessalonians 3:8

neither did we eat bread with any one gratuitously, but with labor and toil, night and day working, that we might not burden any one of you:

Treasury of Scripture Knowledge

Summary

I have seen the travail, which God hath given to the sons of men to be exercised in it.

Bible References

General references

1 Thessalonians 2:9
For you remember, brethren, our labor and toil: night and day working, that we should burden no one of you, we preached unto you the gospel of God.
2 Thessalonians 3:8
neither did we eat bread with any one gratuitously, but with labor and toil, night and day working, that we might not burden any one of you: