تفسير : (lo! they) i.e. the people of mecca (plot a plot (against thee, o muhammad)) they scheme in their state of disbelief, that is to say they bar people from muhammad (pbuh) and from the qur'an; it is also said this means: they plan, in dar al-nadwah, to kill you, o muhammad!
Jalāl al-Dīn al-Maḥallī
تفسير : indeed they, that is, the disbelievers, are devising a plot, they are preparing plots against the prophet (s),