Ms Wall also acknowledged the party leaders in the House who had shown leadership by supporting her bill - Prime Minister John Key, Labour leader David Shearer, Act leader John Banks, United Future leader Peter Dunne, Mana leader Hone Harawira and Maori Party co-leaders Pita Sharples and Tariana Turia.
"Nothing can counteract the very real negative consequences of not passing this bill. But nothing could make me more proud to be a New Zealander than passing this bill.
"I thank my colleagues for simply doing what is just, fair and right.''
New Zealand First voted against the bill at previous readings because the party wanted a public referendum to be held on the issue. This proposal was ruled out of order at the second reading.
The bill is decided by conscience vote, not along party lines. Nearly half of the National Party have supported it so far, and all but three Labour MPs have voted in favour.
Ms Wall said it was important to learn from history, and cited examples of marriage being used as a tool of oppression - the banning of marriage between German nationals and Jews in 1935, and the banning of interracial marriage in South Africa before 1985.
"Excluding a group in society from marriage is oppressive and unacceptable. Today we're embarrassed and appalled by these examples. And in every instance it was action by the state. This is not about church teachings or philosophy. It never has been.
"It's about the State excluding people from the institution of marriage because of their sex, sexual orientation or gender identity. And that's no different from the actions taken in these historical examples.''
Ms Wall stressed that her private member's bill would not legalise criminal offences such as marriage between more than two people, that religious ministers would be able to choose who they married, and that adoption laws would not be changed.
MPs heard the story of a gay mother whose partner had to have her name struck off her daughter's birth certificate when she died, because only one person in a gay couple could be recognised as a parent or guardian.
The law change would allow both people in a gay couple to be legally recognised as a parent of an adopted child.
Ms Wall said there had been few occasions in Parliament when the public gallery was overflowing, with such a crowd only observed otherwise at Treaty of Waitangi settlements. Hundreds more were watching the debate in the Parliament's legislative chamber, and in bars, pubs, and churches around the country.
Outside Parliament, scheduled celebrations were cancelled or dampened by rain, but a group of 30 men paraded down Lambton Quay in wedding dresses.
