How did Antoine Lavoisier help show that water is made from oxygen and hydrogen?

Antoine Lavoisier demonstrated that water is a chemical compound composed of oxygen and hydrogen by building upon the work of other scientists, most notably Henry Cavendish, who had identified a gas he called "inflammable air."1

Lavoisier’s success was rooted in his rigorous application of the law of conservation of mass. By using precise weighing techniques to track all substances entering and emerging from chemical reactions, he was able to account for the gases involved in the process. He identified that "inflammable air" combined with oxygen to form water, and he subsequently renamed the former "hydrogen," which translates to "water producer." This discovery was a vital component of his broader [chemical revolution], which replaced the outdated phlogiston theory with a new system based on oxidation and a modern understanding of chemical elements.12