"We have not an high priest which cannot be reached with the feeling of our infirmities." (Heb.4:15)
Or rather, which cannot have sympathy. 
That is the Greek word.
The word "sympathy" is simply the Greek word transferred, and that is the word which is here used.
Q: What does sympathy mean?
A: It means suffering with.
So we have not an high priest which cannot suffer with our infirmities. Leave out the negatives and what do you have?-We have an high priest who can suffer, and who does suffer with our infirmities."
E.J. Waggoner