And thou, child, shalt be called the prophet of the Highest: for thou shalt go before the face of the Lord to prepare his ways; To give knowledge of salvation unto his people by the remission of their sins, Through the tender mercy of our God; whereby the dayspring from on high hath visited us, (emphasis added)
Whereby the dayspring … – The word “dayspring” means the morning light, the aurora, the rising of the sun. It is called the dayspring “from on high” because the light of the gospel shines forth from heaven. God is its Author, and through His mercy it shines upon people. There is here, doubtless, a reference to Isaiah 60:1-2; indeed, almost the very words of that place are quoted. Compare also Revelation 22:16. Source
Thy Word is a Lamp 