MPs should not "undermine" the UK's position when they vote on the EU bill, Brexit Secretary David Davis says.
Opening two days of debate, Mr Davis said a bid to give Parliament more control would tie ministers' hands and lead to a bad deal for the UK.
MPs then accused each other of trying to "wreck" Brexit and, from the other side, being "zealots" who wanted to sideline Parliament. Earlier the government was hit by its first resignation over Brexit.
Justice Minister Phillip Lee said Parliament was being sidelined and that he could not support "how our country's exit from the EU looks set to be delivered".
Starting the Commons debate, Mr Davis told MPs the bill's "primary purpose" was to ensure a "functioning statute book" on the day the UK leaves the EU, 29 March 2019.
The most tightly-contested amendment is likely to be the call for Parliament to decide what happens next if MPs decide they do not like the UK-EU Brexit deal.