For that he also himself is compassed with infirmity. (Hebrews 5:2)"No one can sympathize with a sufferer except one who feels the same pain, or at least has a vivid recollection of it.
That is what the word itself means. "Sympathy" is made up of two Greek words, which mean, "to suffer with."
The word "compassion" has the same meaning, being formed from two Latin words.
The only reason why the priest ordained of God has compassion on the ignorant and the erring, is because he himself has the same infirmities."
E.J.Waggoner