Cyril of Alexandria
Catena Aurea · Lukasevangelium 11
And I say unto you, Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you. For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened. If a son shall ask bread of any of you that is a father, will he give him a stone? or if he ask a fish, will he for a fish give him a serpent? Or if he shall ask an egg, will he offer him a scorpion? If ye then, being evil, know how to give good gifts unto your children: how much more shall your heavenly Father give the Holy Spirit to them that ask him?
The words, I say unto you, have the force of an oath. For God doth not lie, but whenever He makes known any thing to His hearers with an oath, he manifests the inexcusable littleness of our faith.