Perhaps the Visuddhimagga?
"Mere suffering exists, no sufferer is found;
The deeds are, but no doer of the deeds is there;
Nibbāna is, but not the man that enters it;
The path is, but no traveler on it is seen."
Not a Sutta, however. SN 22.22 offers:
A burden indeed
are the five aggregates,
and the carrier of the burden
is the person.
Taking up the burden in the world
Casting off the burden
Having cast off the heavy burden
and not taking on another,
pulling up craving,
along with its root,
one is free from hunger,
So, the carrier of the burden exists, not ontologically, but existentially. The Visuddhimagga seems to be focusing on the ontological side when it says those lines.