Simba had forgotten who he was. He was the Son of Mufasa, and rightful Heir to the Kingdom of his Father.
How then do we "suffer with him"? Do we have to have our own Garden of Gethsemane, or Die on a Cross? No. We must however go through the pains of Spirit, and learn to Feel as He Felt. To have Godly Sorrow for both our Sins, and the trials of those around us.
If you have forgotten who YOU are, YOU have forgotten the FATHER.
"And now, my sons, REMEMBER, REMEMBER that it is upon the rock of our Redeemer, who is Christ, the Son of God, that ye must build your foundation; that when the devil shall send forth his mighty winds, yea, his shafts in the whirlwind, yea, when all his hail and his mighty storm shall beat upon you, it shall have no power over you to drag you down to the gulf of misery and endless wo, because of the rock upon which ye are built, which is a sure foundation, a foundation whereon if men build they cannot fall."
-- Helaman 5:12
REMEMBER what we are supposed to be doing.