Abba Isaiah of Scetis: Faith in Temptations

 A person who doubts whether God will help him during temptations does not believe in God and is not worthy to be called Christian. A truly believing and pious person, even if he finds himself in the very jaws of the serpent, still believes, even then, that God can rescue him. Thus did the martyrs believe and they fearlessly entered the flaming furnace, and God delivered them because of their unwavering faith. In this way He delivered the Three Youths from the Babylonian furnace, and St. Thekla from the fire and the cruel beasts - all, without a doubt, because of their pure faith.

+Abba Isaiah of Scetis, from Matericon Instructions of Abba Isaiah to the honorable nun Theodora, #52

St. Anatoly of Optima, Saving Temptations

Pride is the culmination of the demonic scheme. But He "Who will have all men to be saved and to come unto the knowledge of the truth"(1 Timothy 2:4) permits the Devil and people to humble us... Since, Matushka, in God's first blessed instrument intended for your healing you do not wish to recognize God's hand, therefore temptations are sent to you... If you are not made wiser, yet more temptations or afflictions will be sent to you, greater than the first. (c.f. St. Mark the Ascetic, "On the Spiritual Law", #46, Philokalia 1)  But let us hasten to humble ourselves, let us endure patiently, guarding ourselves with the fear of God...
+St. Anatoly (Zertsalov) of Optina, from A Collection of Letters to Nuns, Profitable instructions for laymen and monastics, letter 43, Saving Temptations