1 Thessalonians 2:9
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.
Note 12 at 1Th 2:9: The Christian life is not a vacation; at least it wasn't for Paul. Although many traveling preachers may have made themselves financially burdensome to others, that was not Paul's way. From Scripture we know that in Thessalonica (this verse), Corinth (1Co 4:12), and Ephesus (Ac 20:34), Paul maintained his ministry by manual labor.
Although Paul had the right to financial aid from others, he did not want to burden new believers or allow his critics an opportunity to accuse him of being in the ministry just for the money (see note 5 at 1Co 9:6). Ac 18:3 tells us that Paul worked as a tentmaker as he ministered the Gospel of God.