Walk before God in simplicity, and not in subtleties of the mind. Simplicity brings faith; but subtle and intricate speculations bring conceit; and conceit brings withdrawal from God. — St. Isaac of Syria
Let all of us who wish to attract the Lord to ourselves draw near to Him as disciples to the Master, simply, without hypocrisy, without duplicity or guile, not out of idle curiosity. He Himself is simple and not composite, and He wants souls that come to Him to be simple and guileless. For you will surely never see simplicity bereft of humility. — St. John Climacus, from The Ladder of Divine Ascent
Hold faith and humility fast within you; for through them you will find mercy, help, and words spoken by God in the heart, along with a protector who stands beside you both secretly and manifestly. Do you wish to obtain these things, which are a fountain of life? From the very onset take hold of simplicity. Walk before God in simplicity and not with knowledge. Simplicity is attended by faith; but subtle and intricate deliberations, by conceit; and conceit is attended by separation from God. – from The Ascetical Homilies of St. Isaac the Syrian.
A person can be raised up above the earth by two wings, one is simplicity and the other is purity of heart. You must be simple in your actions and pure in your thoughts and feelings. With a pure heart you’ll seek God and with simplicity you’ll find Him and be glad. A pure heart passes through Heavens gate with ease. — Elder Amphilochios Makris