What does 1 Timothy 1:17 mean?

It's not surprising that Paul, who recognizes the mercy of God in his own life, would conclude his testimony with praise. Paul calls God "the King of the ages." In the Greek of this passage, God is literally described as the eternal King. Paul will also use the phrase "King of kings" in 1 Timothy 6:15. Because God alone is the eternal King, we can pray for earthly kings (1 Timothy 2:2), but do not worship them as divine. The Roman practice of emperor worship sometimes created persecution among early Christians, who would not participate. Describing God as the King of the ages presents Him as higher than all authorities or other gods. This was especially important in Ephesus, a major city in which emperor worship took place.

God is also "immortal," meaning He does not die. He is "invisible" (John 1:18), and He is the only God (Exodus 20:1–4; Deuteronomy 6:4–5). He is to be given "honor and glory," indicating all worship and praise, common themes in the Psalms that Timothy would have known well. The closing phrase "forever and ever" can also be translated "to the ages of ages" and complements God as "King of the ages." The word "amen," meaning "be it so," concludes this brief praise.

This verse's depiction of God can be divided into parts which closely parallel Paul's doxology in 1 Timothy 6:15–16:

1 Timothy 1:17	1 Timothy 6:15-16
"To the King of the ages,	"the King of kings and Lord of lords,
immortal,	who alone has immortality,
invisible,	who dwells in unapproachable light, whom no one has ever seen or can see.
the only God, be honor and glory	To him be honor
forever and ever.	and eternal dominion.
Amen."	Amen."