was ich dir sagen

what I tell you

→ was
phrase Uncommon #11,058
what I tell you This is usually followed by a verb such as “will,” “must,” or “will” in the future, which completes the clause.
GE: Hör zu, was ich dir sagen muss.
EN: Listen to what I have to tell you.

Hör bitte, was ich dir sagen muss.

Please listen to what I have to tell you.

Hör gut zu, was ich dir sagen werde.

Listen carefully to what I am about to tell you.

Es gibt so vieles, was ich dir sagen möchte.

There’s so much I want to tell you.

Aber du weißt bereits, was ich dir sagen werde.

But you already know what I'm going to tell you.

— Matrix (1999)

Du mußt genau das befolgen, was ich dir sagen.

You must follow exactly what I tell you.