Neither did we eat any man's bread for nought - We were not supported in idleness at the expense of others. We gave a fair equivalent for all that we received, and, in fact, labored for our own support; see the notes on 1-Thessalonians 2:9.

Neither did we eat any man's bread for naught - We paid for what we bought, and worked with our hands that we might have money to buy what was necessary.
Labour and travail night and day - We were incessantly employed, either in preaching the Gospel, visiting from house to house, or working at our calling. As it is very evident that the Church at Thessalonica was very pious, and most affectionately attached to the apostle, they must have been very poor, seeing he was obliged to work hard to gain himself the necessaries of life. Had they been able to support him he would not have worked with labor and travail night and day, that he might not be burdensome to them; and, as we may presume that they were very poor, he could not have got his support among them without adding to their burdens. To this his generous mind could not submit; it is no wonder, therefore, that he is so severe against those who would not labor, but were a burden to the poor followers of God.

Neither did we eat any man's bread for nought.... Or freely, at free cost, without paying for it; he signifies, that what they ate, they bought with their own money, and lived on no man, without giving him a valuable consideration for what they had; though if they had not paid in money for their food, they would not have ate it for nought, since they laboured among them in preaching the Gospel to them; and such labourers are worthy of their maintenance, Luke 10:7 though the former sense is the apostle's here:
but wrought with labour and travail night and day: not only laboriously preaching the Gospel to them, as often as they could have opportunity, but working very hard and incessantly with their hands, at the occupations and trades they had been brought up to; and that of the Apostle Paul's was a tentmaker, at which he sometimes wrought, thereby ministering to his own, and the necessities of others, Acts 18:3, nor was this inconsistent with his learning and liberal education. It was usual with the Jewish doctors to learn a trade, or follow some business and calling of life; See Gill on Mark 6:3. The apostle's end in this was,
that we might not be chargeable to any of you; or burdensome to them, they being for the most part poor; and the apostles being able partly by their own hand labour, and partly by what they received from Philippi, Philippians 4:16 to support themselves, chose to that they might not lie heavy upon them, and any ways hinder the spread of the Gospel among them, at its first coming to them. And so Maimonides says the ancient Jewish doctors behaved, and with a like view: wherefore, says he (p),
"if a man is a wise man, and an honourable man, and poor, let him employ himself in some handicraft business, even though a mean one, and not distress men (or be burdensome to them); it is better to strip the skins of beasts that have been torn, than to say to the people, I am a considerable wise (or learned) man, I am a priest, take care of me, and maintain me; and so the wise men have ordered: and some of the greatest doctors have been hewers of wood, and carriers of timber, and drawers of water for the gardens, and have wrought in iron and coals, and have not required anything of the congregation; nor would they take anything of them, when they would have given to them.''
(p) Hilchot Mattanot Anayim, c. 10. sect. 18.

eat any man's bread--Greek, "eat bread from any man," that is, live at anyone's expense. Contrast 2-Thessalonians 3:12, "eat THEIR OWN bread."
wrought-- (Acts 20:34). In both Epistles they state they maintained themselves by labor; but in this second Epistle they do so in order to offer themselves herein as an example to the idle; whereas, in the first, their object in doing so is to vindicate themselves from all imputation of mercenary motives in preaching the Gospel (1-Thessalonians 2:5, 1-Thessalonians 2:9) [EDMUNDS]. They preached gratuitously though they might have claimed maintenance from their converts.
labour and travail--"toil and hardship" (see on 1-Thessalonians 2:9).
night and day--scarcely allowing time for repose.
chargeable--Greek, "a burden," or "burdensome." The Philippians did not regard it as a burden to contribute to his support (Philippians 4:15-16), sending to him while he was in this very Thessalonica (Acts 16:15, Acts 16:34, Acts 16:40). Many Thessalonians, doubtless, would have felt it a privilege to contribute, but as he saw some idlers among them who would have made a pretext of his example to justify themselves, he waived his right. His reason for the same course at Corinth was to mark how different were his aims from those of the false teachers who sought their own lucre (2-Corinthians 11:9, 2-Corinthians 11:12-13). It is at the very time and place of writing these Epistles that Paul is expressly said to have wrought at tent-making with Aquila (Acts 18:3); an undesigned coincidence.