The Olivet Discourse reference to the Coming of the Son of Man being like "lightening" flashing "from the east to the west" is actually a poor translation. Jesus is speaking of the light of the morning sun. Lightening doesn't shoot in any particular direction. The sunrise does.

The Coming of God shining like the morning sun is actually a very clear and common theme found throughout the Old Testament.

“The LORD will come from Sinai, and dawn on them from Seir; He will shine forth from Mount Paran, and He will come from the midst of ten thousand holy ones..." (Deuteronomy 33:2)

"God will come from Teman, the Holy One from Mount Paran. His splendor will cover the heavens, the earth will be full of His praise. His radiance will be like the sunlight..." (Hab 3:3–4)

“Arise, shine; for your light has come. The glory of the LORD has risen upon you. For behold, darkness will cover the earth, deep darkness the peoples; but the LORD will rise upon you. His glory will appear upon you." (Isaiah 60:1–3)

Behold, the day is coming, burning like a furnace. All the arrogant and evildoers will be chaff. The day coming will set them ablaze,” says the LORD... But for you who fear My name, the sun of righteousness will rise with healing in its wings..." (Mal 4:1–2)

Ἀστραπή: “Lightning,” also “beam of light” (Lk. 11:36) “Ἀστραπή,” ed. Gerhard Kittel, Theological Dictionary of the New Testament (Grand Rapids, MI: Eerdmans, 1964–), 505.

-Joel Richardson