Then Allah says:

بَلْ قَالُوا إِنَّا وَجَدْنَا آبَاءنَا عَلَى أُمَّةٍ وَإِنَّا عَلَى آثَارِهِم مُّهْتَدُونَ ﴿٢٢﴾

Nay! They say:

"we found our fathers following a certain way and religion (Ummah), and we guide ourselves by their footsteps.''

meaning, they have no grounds for their belief in idolatry apart from the fact that they are imitating their fathers and forefathers who were following a certain Ummah or way, i.e., religion.

The word Ummah is used in a similar manner elsewhere, where Allah says:

إِنَّ هَـذِهِ أُمَّتُكُمْ أُمَّةً وَاحِدَةً

And verily, this your religion (Ummah) is one religion. (23:52),

and they said;

... وَإِنَّا عَلَى آثَارِهِم ...

and we by their footsteps,

means, behind them.

... مُّهْتَدُونَ

We guide ourselves,

This is their claim with no evidence.

Then Allah points out that what these people say was already said by those who were like them among the nations of the past who disbelieved in the Messengers. Their hearts and their words are similar.

كَذَلِكَ مَآ أَتَى الَّذِينَ مِن قَبْلِهِمْ مِّن رَّسُولٍ إِلاَّ قَالُواْ سَـحِرٌ أَوْ مَجْنُونٌ

أَتَوَاصَوْاْ بِهِ بَلْ هُمْ قَوْمٌ طَـغُونَ

Likewise, no Messenger came to those before them but they said: "A sorcerer or a madman!''

Have they transmitted this saying to these?

Nay, they are themselves a people transgressing beyond bounds! (51:52-53)