An Etymological Dictionary of the German Language/Annotated/üben

üben, verb, ‘to practise, exercise,’ from Middle High German üeben, Old High German uoben (from *ôbjan), weak verb, ‘to set agoing, execute, venerate,’ corresponding to Old Saxon ôƀian, ‘to celebrate,’ Dutch oefenen, ‘to exercise, look after,’ Ofc. œ́fa, ‘to practise.’ Allied to Old High German uoba, ‘celebration,’ uobo, ‘tiller of the soil.’ The Teutonic root ôb, ‘to execute,’ contained in these cognates, seems to have been originally used of tilling the ground and of religious acts. To this corresponds, according to the permutation of consonants, the Aryan root ō̆p, with which are allied Sanscrit ā̆pas, neuter, ‘work’ (especially religions work), and Latin ŏpus, neuter, ‘work’ (connected with ŏperari, especially, ‘to sacrifice’).