This sentence by Pascal, a philosopher of the seventeenth century , is best known for Pascal‘s thought. It is now used indiscriminately to justify all the irrational human behavior. This is a total contradiction with the spirit of this quote from Pascal.
Indeed, Pascal discusses religious belief: belief, he says, can not be justified by the knowledge of God. The existence of God can not be justified rationally. You have to believe, Pascal says, because it is absurd.
For him, the truth is accessible by two ways the heart and mind. What Pascal calls the heart is the faculty that makes us know things by intuition and immediate, closely connected to the body, includes everything we understand by instinct, sensitivity, sentiment. The reason only infer and conclude from first principles, they, we are provided directly by the heart. The heart is the first, anterior superior mind.
So the heart and not for the reason that we must apprehend religious truths. And it is also the heart that we must, can, convince the skeptics.
The heart has its reasons that reason reflects a theory of religious belief, therefore, that the heart is a better path to God than reason, limited.