The pronoun in 'min qablihi' refers to the Qur'an or the Messenger. The meaning is that they attributed the worship of others besides Allah to the will of Allah: a saying they spoke without knowledge. Then it was said: 'Or have We given them a Book before this Book to which they hold, in which we attributed disbelief and vile acts to Us?' So they obtained knowledge of that from the direction of revelation, and they held fast to that Book and used it as an argument. Rather, they have no proof to hold onto except their saying: 'Indeed, we found our forefathers on a nation, on a religion.' It was also read as 'ala immatin' with a kasra, and both are from 'umm', which means the aim. So the 'umma' is the path that one aims for, like a journey to the destination. And the 'umma' is the aunt that is upon the aim, which is the one who intends. It was said: 'on a blessing and good state, guided by their traces' is the news of 'inna'. Or the adverb is a connection for 'muhtadun'.