Jerrold Nadler actually said...

You are also proving our point for the American people to see. The President is intent on obstructing our legitimate oversight.

what we're doing is very clear, it's been very clear, it continues to be very clear. The Speaker has backed us at every point along the way.

this is a formal impeachment proceeding.

An impeachment inquiry is when you consider only impeachment. That's not what we're doing. We're investigating all of this.