Sound reason

What you call sound reason we Christians take to be a reason so infirm, so darkened and so far gone astray, that there can be no healing for it except by cutting off, with the sword of faith, and renouncing all the learning that has gone into its formation. If we take it for a sound reason, basing ourselves on a foundation that is uncertain, tottering, indefinite, constantly changing -- then it, being sound, will renounce Christ too.
St. Ignatius (Brianchaninov)

You must know Christ!

You reason about salvation, yet you do not know what salvation is, why men are in need of it, and finally, you do not know Christ, the only means of our salvation. ... You must know Christ! You must realize that you do not know Him, that you deny Him if you acknowledge salvation possible without Him for any kind of good works! He who acknowledges salvation to be possible without Christ denies Christ and, perhaps without knowing it, falls into the grave sin of blasphemy. ... To be sure, you had a revelation from above on this subject, concerning what is contrary and what is not contrary to Divine mercy? -- No, it was sound reason that pointed it out. Ah, your sound reason! Still, where in your sound reason did you find out that it was possible to understand, with your own limited human mind, what is contrary and what is not contrary to the Divine mercy?
St. Ignatius (Brianchaninov)

The end of reason

Western man, having through the exclusive development of his abstract reason lost faith in all convictions not derived from it, has now owing to that same development, lost his last faith-faith in the omnipotence of that reason.
Ivan Kireevskii