Majjhima Nikaya 1:69
SUJATOākiñcaññāyatanaṁ ākiñcaññāyatanato saññatvā ākiñcaññāyatanaṁ maññati, ākiñcaññāyatanasmiṁ maññati, ākiñcaññāyatanato maññati, ākiñcaññāyatanaṁ meti maññati, ākiñcaññāyatanaṁ abhinandati.
Having perceived the dimension of nothingness as the dimension of nothingness, they conceive it to be the dimension of nothingness …