We find that during certain prayers we remain silent even though the Qur'an directs us to utter our prayers in a moderate volume (neither too loud nor too soft). Some would argue that verse of the Qur'an is referring to Salaat the system of following Allah's commands closely. And it means call people to Allah's way in a moderate manner (not too aggressively neither too meekly).
The verse in question commands the Prophet (sws) to recite the Qur'an in moderate tone in the prayer that is obligatory on his exclusively. This we conclude form the fact that he taught the believers to pray in a certain way. It inlcudes prayers which are said loudly and prayers which are whispered. Then there are parts which are said loundly and parts which are whispered. That the Prophet (sws) taught us the prayer this way is established absolutely without a shadow of doubt. The Prophet (sws) instituted the Prayer among the generation of the Companions and they transmitted it to the next generation with their consensus. The successors too received and passed it on. There has not been a singe generation in the entire history of Muslims where the believers left the prayer to be rediscovered later on. It has travelled through the generations with thier consensus. This makes it absolutely authentic.
Since this is not this prayer which is referred to in the verse and since the context leads us otherwise we believe that the directive is not regarding the general prayer but the tahajjud prayer which was specifically obligator for the Prophet (sws). The words used in the erse and the style of expression does not allow us to take it to mean a system of following Allah's commands.