God is not only to be known in His blessed and incomprehensible being, for this is something which is reserved for His saints in the age to come. He is also known from the grandeur and beauty of His creatures, from His providence which governs the world day by day, from His righteousness and from wonders which He shows to His saints in each generation.
John CassianIt is impossible for the mind to remain undisturbed by thoughts, but anyone serious about the matter can certainly permit them entry or drive them away, and although their origin does not lie entirely under our control we can choose to approve of them and to adopt them.
John CassianWe are often indifferent to our brethren who are distressed or upset, on the grounds that they are in this state through no fault of ours. The Doctor of souls, however, wishing to root out the soul's excuses from the heart, tells us to leave our gift and to be reconciled not only if we happen to be upset by our brother, but also if he is upset by us, whether justly or unjustly; only when we have healed the breach through our apology should we offer our gift.
John CassianPerfection... is clearly not achieved simply by being naked, by the lack of wealth or by the rejection of honors, unless there is also that love whose ingredients the apostle described (cf. I Cor. 13) and which is to be found solely in purity of heart. Not to be jealous, not to be puffed up, not to act heedlessly, not to seek what does not belong to one, not to rejoice over some injustice, not to plan evil - what is this and its like if not the continuous offering to God of the heart that is perfect and truly pure, a heart kept free of all disturbance?
John CassianIf you wish to attain to true knowledge of the Scriptures, hasten to acquire first an unshakeable humility of heart. That alone will lead you, not to the knowledge that puffs up, but to that which enlightens, by the perfecting of love.
John CassianIf the kingdom of God is within us and that is a kingdom of justice, of peace, and of joy then whoever remains with these virtues is certainly in the kingdom of God. By contrast, all who deal in unrighteousness, in discord, and in death-bearing gloom have taken their stand in the kingdom of the devil, in hell and in lifelessness. It is by these tokens that the kingdom of God or of the devil is recognized.
John Cassian