When does life begin according to the bible?

Genesis 2:7 is clearest. The first human became a "living being" (nefesh hayah, "a living breath") when God blew into its nostrils and it started to breathe. Human life begins when you start breathing, biblical writers thought. It ends when you stop. That’s why the Hebrew word often translated "spirit" (ruah) - "life force" might be a better translation