Disable past dates or display error message?

I am working on a project where there is a datepicker field. Users are not allow to choose past dates(only current and future dates allow). Right now we have two options to design this, which is either to :

  1. Disable past dates from the datepicker
  2. Allow user to choose past dates and display error message if user choose past date

Which option should I choose and what are the supporting reasons? Need concrete reasoning to convince other team members.

Any advice, help or article related would be a great help. Thanks in advance!