As you probably know, if perhaps not by chapter and verse, in 2 Thessalonians St. Paul wrote:
In fact, when we were with you, we instructed you that if anyone was unwilling to work, neither should that one eat. [2 Thes. 3:10]
Some want to claim this as a general economic principle, in particular using it as a basis for welfare programs.
This strikes me as a misreading of the passage.
2 Thessalonians is a very brief letter, written to a well-established church ("we ourselves boast of you in the churches of God" [1:4]) in large part to counter some errors that had emerged since St. Paul was last there:
We ask you, brothers, with regard to the coming of our Lord Jesus Christ and our assembling with him, not to be shaken out of your minds suddenly, or to be alarmed either by a "spirit," or by an oral statement, or by a letter allegedly from us to the effect that the day of the Lord is at hand. [2:1-2]
In the verses immediately prior to 3:10, St. Paul reminds the Thessalonian church of what he taught them, by word and by example:
We instruct you, brothers, in the name of our Lord Jesus Christ, to shun any brother who conducts himself in a disorderly way and not according to the tradition they received from us. For you know how one must imitate us. For we did not act in a disorderly way among you, nor did we eat food received free from anyone. On the contrary, in toil and drudgery, night and day we worked, so as not to burden any of you. Not that we do not have the right. Rather, we wanted to present ourselves as a model for you, so that you might imitate us. [3:6-9]
When St. Paul writes "whoever will not work should not eat," he is not enunciating a general moral principle, but a specific means of correcting those in error. The non-working Thessalonians he has in mind are not shirkers looking to grift a meal, but Christians led astray by the false teaching that Jesus' return is imminent, and therefore existing food supplies will suffice. By refusing to feed them, the faithful Christians of Thessalonia would be performing a corrective act of mercy.
It's not laziness St. Paul is concerned with in this letter, but heterodoxy.
That doesn't mean it's not true that whoever will not work should not eat, but it can't be proven from this verse.
And if you do want to prove it from Scripture, you need to deal with such verses as, "Give to the one who asks of you, and do not turn your back on one who wants to borrow."