After Al Samh ibn Malik was killed at the Battle of Toulouse in 721 (102 A.H.) by the forces of Duke Odo of Aquitaine, Abdul Rahman took over the command of Eastern Andalus. He was briefly relieved of his command, when 'Anbasa ibn Suhaym Al-Kalbi was appointed in 721 (103 A.H.). After 'Anbasa was killed in battle in 726 (107 A.H.) in Gaul, several successive commanders were put in place, none of whom lasted very long.
Invasion of Gaul and Tours
Arab historians unanimously praise Abdul Rahman as a just and able administrator and commander, and bestow on him the honor of being the best governor of Andalus. Also, he did not take sides in the ethnic and tribal divisions that plagued Andalus under other rulers. Evidence of his fairness and importance as a ruler was demonstrated in the aftermath of his death at the Battle of Tours. Without his leadership and guidance, the other commanders were unable to even agree on a commander to lead them back into battle the following morning. The effect of the death of Abdul Rahman on both Islamic and world history was profound.
His son attempted another invasion of Gaul under the Caliph's instructions in 736, this time by sea. This naval invasion landed in Narbonne in 736 and moved at once to reinforce Arles and move inland. Charles again descended on the Provençal strongholds of the Muslims. In 736, he retook Montfrin and Avignon, and Arles and Aix-en-Provence with the help of Liutprand, King of the Lombards. Nîmes, Agde, and Béziers, held by Muslims since 725, fell to him and their fortresses were destroyed. He crushed one Muslim army at Arles, as that force sallied out of the city, and then took the city itself by a direct and brutal frontal attack, and burned it to the ground to prevent its use again as a stronghold for Muslim expansion. He then moved swiftly and defeated a mighty host outside of Narbonnea at the River Berre, but failed to take the city. In five short years, he had incorporated Muslim heavy cavalry equipment and tactics into his forces, and was able to crush the invading armies, and leave the Muslim forces isolated in Narbonne, which his son Pippin would retake in 759.
Both western and eastern historians agree that had Abdul Rahman prevailed at Tours, he would probably have conquered all of Christian Europe, Martel and his Frankish Army being all that stood between Islam and Rome itself,  and all history would have been far different. "There were no further Muslim invasions of Frankish territory, and Charles's victory has often been regarded as decisive for world history, since it preserved western Europe from Muslim conquest and Islamization."