The Old Testament and the Qur'an are both rather unambiguously violent texts, but there are important differences. In the Old Testament, God tends to command or condone violence in specific situations, i.e. "I command you, the tribe of Israel, to go forth now and annihilate tribes x, y and z and take their land." In the Qur'an, violence is more open-ended and broad in scope: "I command you to wage war against the unbelievers for all time. It is your religious duty to kill, convert or subjugate all non-Muslims". While the Old Testament gives historical accounts of wars that were fought in the past, the Qur'an is more concerned with laying down the rules of how and against whom wars should be fought in the future. There's a big difference between "we had a battle and God was on our side, so we won", and "here's a step by step guide to world domination".