The saying, “We have returned from the lesser jihad to the greater jihad.” is a false, fabricated hadeeth which has no basis.
Ibn Taymiyyah said: “This hadeeth has no sources and nobody whomsoever in the field of Islamic knowledge has narrated it. Jihad against the disbelievers is the most noble of actions and moreover it is the most important action for the sake of mankind.” [Al-Furqaan, pp.44-45]
Al-Khateeb Al-Baghdadi reports it as da’eef (weak) due to the narrator Khalaf Ibn Muhamad Ibn Isma’eel Al-Khiyam.
Al-Hakim said: “His hadeeths are unreliable.”
Abu Ya’la Al-Khalili said: “He often adulterates, is very weak and narrates unknown hadeeth.” [Mashri Al-Ashwaq, by Ibn Nuhas, 1/31]
There is also the narrator Yahya Ibn Al-Ula, who is a known liar and forgerer of hadeeth. [Ahmad]
Amru Ibn ‘Ali, An-Nisaa’i and Daraqutni said: “His hadeeth are renounced.”
Ibn Adi said: “His hadeeth are false.” [Tahzeeb At-Tahzeeb, 11/261]
Ibn Hajr said: “He was accused of forging hadeeth.” [Al-Taghrib]
Adh-Dhahabi said: “Abu Hatim said that he is not a strong narrator. Ibn Ma’een classified him as weak and Ad-Daraqutni said that he is to be neglected.”