﴿ وَإِن كَانُوا۟ مِن قَبْلِ أَن يُنَزَّلَ عَلَيْهِم مِّن قَبْلِهِۦ لَمُبْلِسِينَ ﴾

“even though a short while ago, [just] before it was sent down upon them, they had abandoned all hope!”

Though indeed before it was sent down upon them before that min qablihi is repeated for emphasis they had been despondent despairing of its sending down.