Let us give ourselves to God…

Let us give ourselves to God without any reserve, and let us fear nothing. He will love us, and we shall love Him. His love, increasing every day, will take the place of everything else to us. He will fill our whole hearts; He will deprive us only of those things that make us unhappy. He will cause us to do in general, what we have been doing already, but which we have done in an unsatisfactory manner; whereas, hereafter, we shall do them well, because they will be done for His sake. Even the smallest actions of a simple and common life will be turned to consolation and recompense. We shall meet the approach of death in peace; it will be changed for us into the beginning of the immortal life.
–François Fénèlon (1651-1715)

We can reach spiritual maturity…

We do not reach the final stage of spiritual maturity through divine power and grace alone, without ourselves making any effort; but neither on the other hand do we attain the final measure of freedom and purity as a result of our own diligence and strength alone, apart from any divine assistance. “If the Lord does not build the house, it is said, and protect the city, in vain does the watchman keep awake, and in vain do the laborer and the builder work.”  (Psalm 127:1)
–Saint Macarius the Great (295-392)

Concealed sins of the soul…

The virgin soul that desires to be united to God must keep itself pure not only from overt sins like unchastity, murder, theft, gluttony, backbiting, falsity, avarice, greed and so on; but to an even greater degree it must keep itself pure from sins that are hidden, such as desire, self-esteem, love of popularity, hypocrisy, love of power, wiliness, malice, hatred, unbelief, envy, self-love, affectation and other things of this kind. According to Scripture, these concealed sins of the soul are just as pernicious as the overt sins.
–Saint Macarius the Great (295-392)

The kingdom is within you…

Be peaceful within yourself, and heaven and earth will be at peace with you. Be diligent to enter into the treasury that is within you, and you will see the treasury of Heaven: for these are one and the same, and with one entry you will behold them both. The ladder of the Kingdom is within you, hidden in your soul. Plunge deeply within yourself, away from sin, and there you will find steps by which you will be able to ascend.
–Saint John Climacus (c. 525-606)