Is The Prayer Correct From One Prayed Ishaa And Forgot To Do The First Tashahud, And Thus Stood Up But After He Had Completely Stood Up For The Third Rakaa', He Sat Back Down, And Then Completed Two Rakats And Did The Prostration Of Forgetfulness - Shaykh Muhammad Ibn Hizaam, Imam Ahmad Bin Hanbal And Shaykh Ibn Uthaymeen