Then they intended to design a plan against him, but We brought them low.
They schemed against him, but we made them the losers.
Their desire was to outwit him, but We made them to be the humiliated
And they designed a plan against him, but We brought them low
So they intended/wanted a conspiracy/harm with (for) him, so We made/put them the lowest/meanest
They plotted a plan against him and God defeated them in their own plan [as the fire did not have any effect upon Abraham.]
So they tried to execute their evil scheme upon him – We therefore degraded them. (Allah saved him, by commanding the fire to turn cool)
Thus they designed an evil design against him, but WE made them most humiliated
So they attempted to play a trick against Ibrahim (Abraham), but We humiliated them (when the fire eventually turned into a flower garden)
Thus they designed a plan against him, but We made them to be the most humiliated
So they plotted a plot against him, but We made them the lowest