The hadith of Ibn ʿUmar is a ḥasan ṣaḥīḥ hadith. We do not know it except through this chain, from the narration of ʿĀṣim—namely, Ibn Muḥammad ibn Zayd ibn ʿAbd Allāh ibn ʿUmar(1).

And the hadith of ʿAbd Allāh ibn ʿAmr is better.

‌‌5 — Chapter: What has been reported concerning the concession for lying and deception in war

1770 — Aḥmad ibn Manīʿ and Naṣr ibn ʿAlī narrated to us, both saying: Sufyān narrated to us, from ʿAmr ibn Dīnār, who heard Jābir ibn ʿAbd Allāh saying: The Messenger of Allah, peace and blessings be upon him, said: "War is deception."(2)

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= i.e., ʿāṣī (disobedient), as in His saying: {Devils of mankind and jinn} [al-Anʿām: 112], meaning: the disobedient ones among mankind and jinn. End quote.

(1) Thus in (Ẓ), and in the rest of the sources: "ʿAmr," which is an error.
Note: After this, in the printed edition occurs: "Muḥammad said: He is trustworthy and truthful, and ʿĀṣim ibn ʿUmar al-ʿUmarī is weak in hadith; I do not narrate anything from him." This does not appear in our manuscript sources.

(2) A ṣaḥīḥ hadith, and it was recorded by al-Bukhārī (3030), Muslim (1739), Abū Dāwūd (2636), and al-Nasāʾī in al-Kubrā (8643). It is in al-Musnad (14177) and Ṣaḥīḥ Ibn Ḥibbān (4763).
His saying: "khadʿah" — al-Khaṭṭābī said in Maʿālim al-Sunan 2/269: Its meaning is the permissibility of deception in war, even though it is prohibited in other matters. This word is narrated in three forms: khadʿah with a fatḥa on the khāʾ and sukūn on the dāl, and khudʿah with a ḍamma on the khāʾ and sukūn on the dāl, =