Dear Shaykh, is the following saying of Imam Ahmad Ibn Hanbal, may Allaah have mercy with him, true? “Verily, the Khawaarij, they are the Murji’ah.” How could this be possible? Are the Khawaarij and the Murji'ah two different sects? What did Imam Ahmed intend with these word's? May Allaah reward you Shaykh.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger. 

The statement that you mentioned in the question was mentioned in the book entitled As-Sunnah. Prof. Dr. Safar al-Hawali said about the meaning of this statement in his book entitled Thaahirat Al-Irjaa’ fi Al-Fikr Al-Islaami, “Imaam Ahmad said a statement that may be difficult to understand, which is his saying in the book As-Sunnah, which was published along with the book Ar-Rad ‘ala Az-Zanaadiqah: 'The Khawaarij are the Murji'ah.'”

Then Dr. Al-Hawali said:

“Interpreting it to refer to the irjaa' (postponement) of the Companions is possible [i.e. postponing the judgment on ‘Uthmaan and ‘Ali ]. But as regards the general irjaa' that is related to the faith, then this cannot be possible – except if the statement is incomplete or distorted – this is for instance if one says, 'The Khawaarij accuse Ahlus-Sunnah that they are Murji’ah because they do not authoritatively assert that a specified person who has committed a grave major sin is eternally in Hellfire. So Imaam Ahmad responded to them by saying that it is them who are the Murji’ah, because they do not authoritatively assert that ‘Uthmaan and ‘Ali will enter Paradise although it is authentically proven in Islamic text sthat they will enter Paradise.' Rather, the Khawaarij either consider that ‘Uthmaan and ‘Ali are non-Muslims – such as the case of those who are extremists amongst them – or they postpone their matter and do not authoritatively assert anything about them as is the case of the Murji’ah amongst them. Hence, they deserve to be described by Ahlus-Sunnah by such a name, because if someone doubts an obvious and authentic matter (i.e. the destiny of ‘Uthmaan and ‘Ali), then he deserves this reprehensible title more than those who do not assert anything about a matter that they have no knowledge of (i.e. the destiny of the one who has committed a grave major sin).”

There is no doubt that there is a difference between the Murji'ah and the Khawaarij; for more benefit in this regard, please refer to fataawa 91651, 20932 and 91562.

Allaah knows best.