Melania brought it up to him and nudged multiple times. What does this mean?

"At Trump’s first inauguration in 2017, he used two Bibles—one his mother gave him and the Bible that Lincoln was sworn in with at his first inauguration.

Some presidents did not use a Bible to take the oath of office, including Theodore Roosevelt, who did not use anything when he was sworn into office in 1901, and John Quincy Adams, who chose a legal book for his 1825 swearing-in, to signify his responsibility to uphold the U.S. constitutional law." From Time.com