Note use of hereby enter into in the following Pleistocene-era lead-in:
NOW THEREFORE, the parties hereby enter into this Agreement to set forth their mutual promises and understandings, and mutually acknowledge the receipt and sufficiency of valuable consideration in addition to the mutual promises, conditions and understandings set forth below.
And note the same in the following concluding clause:
IN WITNESS HEREOF, the parties hereby enter into this Agreement and affix their signatures as of the date first above written.
The problem is that the hereby in language of performance means, in effect, “by means of this agreement.” So hereby enter into this agreement means “enter into this agreement by means of this agreement.”
Cue brains imploding.
I just say The parties therefore agree as follows. (Omit the therefore if you don’t have recitals.)