Herod's priests, who had God's Word, told the Magi the prophecy of Bethlehem (Matthew 2:1-6).
The pagan Magi didn't have God's Word so God spoke to them through something they did have: stars.*
This is significant because it proves that people without God's Word aren't abandoned. If they sincerely seek Jesus, they will find Him.
But why does this seem to happen so rarely?
It probably happens more than we realize, but the sad fact is that most people refuse God's call.
There were thousands of pagans who studied the stars, but only these wise men responded. (1)
There were thousands of Jews who studied the Old Testament, but even the priests in Herod's court showed no interest in checking out the birth of Christ.
God speaks to pagans without His Word (See Wait for the English) and He speaks through His Word to us who have it. But only genuine seekers respond.
The Magi are a living proof of Jeremiah 29:13: "You will seek me and find me when you seek me with all your heart."
*I am not saying God speaks through pagan gods. I am saying that He will employ different means to get people's attention so they will find Jesus, the true God.
(1) Rahab's story is similar. See The Prostitute and She Had a Past and a Future.