This is because [this reconciliation between the ḥadīths] negates contagion in principle, completely, as is stated explicitly in the authentic reports.
For when innovations which oppose the ḍīn of the Messengers appear, Allāh seeks revenge from whoever opposes the Messengers and aids them (the Messengers)...
Indeed, the affair [of rule] being destined for the kings and their deputies from the rulers, judges and leaders [who are not upright] is not due to the deficiency in them alone...
Is it from the manhaj (methodology) of the Salaf to criticise the rulers from the mimbar (the pulpit)? And what is the manhaj of the Salaf with respect to advising the rulers?
And reflect in His, the Most High's wisdom in making the kings of the servants, their leaders and their rulers to be of the same type as the actions [of the servants].
Imām Aḥmad (along with Imām Mālik) was upon the view of negating contagion [as a matter of superstition] and eating with the sick (leper) with trust upon Allāh.