God created the stars and everything else in the universe with the intention of it being a witness to His power and glory and not as a means to guide us or to foretell the future. God alone knows and holds the future in His hands. 

The Bible also explicitly commands us not to look to the stars for guidance. In the ancient world, people would often attempt to discern the future by using all kinds of mediums, not just through astrology but also magic, omens, idol worship, sorcery, communion with the dead, and so forth. 

In Deuteronomy, God warns the Israelites not to participate in any of these.  

Deuteronomy 18:9-13 (NKJV)

9. “When you come into the land which the Lord your God is giving you, you shall not learn to follow the abominations of those nations.

10. There shall not be found among you anyone who makes his son or his daughter pass through the fire, or one who practices witchcraft, or a soothsayer, or one who interprets omens, or a sorcerer,

11. or one who conjures spells, or a medium, or a spiritist, or one who calls up the dead.

12. For all who do these things are an abomination to the Lord, and because of these abominations the Lord your God drives them out from before you.

13. You shall be blameless before the Lord your God.

But why did God warn against this? 

Because such things are not only deceptive and unreliable, they can also easily influence someone under the control of the occult spiritual powers that are hostile to God.

In addition, astrology has other problems besides these biblical warnings:

• Different astrologers give various interpretations of the same horoscope chart.
• Astrologers disagree on the number of signs of the zodiac. Suggestions include twelve, eight, ten, fourteen, twenty-four. The number of signs influences the interpretation of the data.
• What is the basis of astrological authority? Who determines how many signs of the zodiac there are? How do we know the meanings of the various planets? All this seems arbitrary.
• How do we explain the different experiences of twins?
• How do we explain disasters where many people of different zodiac signs experience the same fate, such as a plane crash?
• Studies show a prediction failure rate of 90 percent or worse for astrologers.

Christians should have no business in be fooling around with horoscopes. The danger of doing so just opens our minds to demonic suggestions. It isn’t that horoscopes can tell you what you are like, but their suggestions can make you into something the system wants you to be. People who often listen / read up on their horoscopes end up patterning their lives in such a manner until they are fully transformed into their horoscopes.

Act 7:43 speaks of how Israel rebelled against god by worshipping “the star of your god Remphan”, which was the worship of the stars (something completely forbidden by God). The reason is because the stars cannot tell your future, neither can they describe your present. Like the horoscopes today, such idolatry was just a means to capture people’s fancy so that the demons could persuade them towards a specific behaviours.  

In conclusion, anyone using such mediums should turn to the God of truth. And even when our future is unclear, we can have hope in the promise that God would guide us through it all.