"Have you even read the United States Constitution? I will gladly lend you my copy," Khizr Khan said during his speech last week at the Democratic National Convention.

>> Watch the video from Newsy

That moment — when the father of a Muslim U.S. soldier killed in Iraq addressed Donald Trump directly — has been played many times over the past few days.

Khan said that if Trump's proposed ban on Muslims entering the U.S. had been enacted years ago, his son would never have been in the country, let alone a soldier who gave the ultimate sacrifice.

>> Here's how Republicans are responding to Trump's comments about the Khan family

That moment appears to have improved sales for a pocket-size Constitution.

The $1 Pocket Constitution made its way to the top of Amazon's list of bestselling books Saturday afternoon. As of Tuesday morning, it was No. 2 on the list.

>> Khizr Khan: Trump's comments 'typical of a person without a soul'

But you don't need to buy one. A quick Google search for "free Constitution" leads you to a site where you can print one. Or you can go to the ACLU's website. It's running a promotion through the election that makes the pocket-size version free using a coupon code.

The sales increase came as Trump and the Khans engaged in a public back-and-forth regarding Trump's statement about the speech.

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This video includes clips from the Democratic National Convention and images from Twitter / @realDonaldTrump and Getty Images.