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.
10 Ye are witnesses, and God also, how holily and justly and unblameably we behaved ourselves among you that believe: 11 As ye know how we exhorted and comforted and charged every one of you, as a father doth his children, 12 That ye would walk worthy of God, who hath called you unto his kingdom and glory.
Paul worked as a tentmaker to supply his own needs so as not to ask for wages of the people to whom he was preaching. This is evidenced by his actions in Corinth.
Acts 18:1 ¶ After these things Paul departed from Athens, and came to Corinth; 2 And found a certain Jew named Aquila, born in Pontus, lately come from Italy, with his wife Priscilla; (because that Claudius had commanded all Jews to depart from Rome:) and came unto them. 3 And because he was of the same craft, he abode with them, and wrought: for by their occupation they were tentmakers.
In early America Baptist preachers were not expected to live off of salaries from their congregations like other denominations of Protestant Christians. A preacher was to labor for his bread outside of his work for his church. In a world of ministers supported by taxes it would have been a tremendous burden on a poor congregation to have to support a preacher and his family entirely from offerings and tithes.
Paul wanted to devote himself solely to ministering of the gospel to the church without the burden of taking money from them. He worked night and day either supplying his own basic needs or to the ministering of the gospel. He was a busy man at all times.
Paul’s efforts were always to be above reproach, to purposefully give no one grounds for criticism that he was an exploiter or a fake.
Acts 24:16 And herein do I exercise myself, to have always a conscience void of offence toward God, and toward men.
Notice in another place how he likened his care for his flock to a father urging his children to do right, which is why it was so important to him to set an example.
1Corinthians 4:14 ¶ I write not these things to shame you, but as my beloved sons I warn you.
15 For though ye have ten thousand instructors in Christ, yet have ye not many fathers: for in Christ Jesus I have begotten you through the gospel.
Paul’s purpose was to see the Thessalonian church set a good example as Christians in a heathen world, as worthy of the God who called them into His kingdom and His glory.