enter into

  1. (transitive, law) To become legally committed to.
    One must be of legal age to enter into a contract.
  2. (transitive) To engage in a formal or informal process.
    The country entered into peace talks with the militants.
    • 1977, Agatha Christie, An Autobiography, Part I, chapter4:
      An indulgent playmate, Grannie would lay aside the long scratchy-looking letter she was writing (heavily crossed ‘to save notepaper’) and enter into the delightful pastime of ‘a chicken from Mr Whiteley's’.
  3. (transitive) To be relevant; to be a contributing factor.
    He did the crime and will go to jail - the fact that he did not know it was illegal does not enter into it.