Praise be to Allah.
Khaalid ibn al-Waleed (may Allah be pleased with him) is the knight of Islam, the Sword of Allah unsheathed against His enemies, leader of great conquests who was present in many decisive battles in Islamic history. He was a man of bravery, strength and courage against the enemy; on the day of Mu’tah seven swords were broken in his hand, as was narrated by al-Bukhaari in his Saheeh.
He had a great love of jihad in support of the religion of Allah and to subdue the forces of evil, kufr and tyranny. Jihad distracted him from all worldly preoccupations, to such an extent that he used to say: “There is no night in which I was given a bride that I love that was more dear to me than a night of severe cold and ice on a campaign in which I attacked an enemy the following morning. Narrated by Abu Ya‘la.
And he (may Allah be pleased with him) said when he was dying: I sought to be killed in a place where death is usually expected (i.e., the battlefield) but it was decreed for me to die in my bed. There is no deed of mine that gave me greater hope, after [saying] la ilaaha ill-Allah, than a night that I spent with a shield in my hand and it rained until morning, in preparation for raiding the kuffaar.
Then he said: If I die, then look at my weapons and my horse, and give them (for jihad) for the sake of Allah.
His love for and preoccupation with this great act of worship (jihad for the sake of Allah) distracted him from other acts of worship such as narrating hadeeth and memorizing the Holy Qur’aan.
He (may Allah be pleased with him) said: Jihad for the sake of Allah kept me from a great deal of recitation. Narrated by Ibn Abi Shaybah in al-Musannaf (4/214) and classed as saheeh by al-Haafiz ibn Hajar in al-Mataalib al-‘Aaliyah (4/277); also narrated by al-Haythami in Majma‘ al-Zawaa’id (9/353),
This preoccupation was not something blameworthy; rather it was a preoccupation that brought glory to all of Islamic history and spread the light of Islam throughout the world which the kaafir tyrants tried to extinguish. There is nothing blameworthy in that, for “everyone is helped to do that for which he was created.” Among the Sahaabah there were scholars, fuqaha’, qaadis (judges), brave men, mujaahideen, those who gave in charity and those who devoted themselves to worship, according to their various abilities and the talents that Allah granted to them.
It is not wise for a person to leave that which he does well and excels at for something in which his achievements will be like those of anyone else, or less, and in which he will not excel.
The words of Khaalid (may Allah be pleased with him) quoted above do not mean that he did not memorize any more than three soorahs, as mentioned in the question. But it does mean that he was not like the hafizes and scholars such as ‘Abd-Allah ibn Mas‘ood, Ubayy ibn Ka‘b and others, based on the fact that he said: “Jihad for the sake of Allah kept me from a great deal of recitation,” and he did not say: “… kept me from recitation.” Jihad kept him from learning a great deal, but not keep him from reciting at all.
But stirring up such doubts and criticism about Khaalid (may Allah be pleased with him) may be motivated by the fact that Khaalid was a sword unsheathed against idols and false gods. Therefore, today you find the enemies of Islam striving hard to undermine his character and cast aspersions on his achievements, and they do not know that a sword that Allah has unsheathed against the kuffaar can never be sheathed again and that this great leader has become one of the symbols of courage, bravery and military genius. Thus were the men around the Messenger (blessings and peace of Allah be upon him), beacons of action, sacrifice, nation-building, values and morals.
We ask Allah to enable us to follow in their footsteps and make us among those who follow them in truth.
And Allah knows best.