THEY DID NOT OBEY HIM

"MY GOD WILL CAST THEM AWAY, BECAUSE THEY DID NOT OBEY HIM; And they shall be wanderers among the nations."
Hosea 9:17 (NKJV)

Comment: The Sin of the Israelites which they were being accused of in the above Bible passage is, THEY DID NOT OBEY HIM—God.
Obedience to God; living according to His precepts, principles, or commands, is the major key to having a good communion with Him. Whatever someone, a believer, would become in God, His Kingdom, starts, or have its foundation, with the doing or practicing of His written Word, plus other specific instructions given to the individual believer.

If this is missing in the life of a person who claims to be a Believer, his or her communion or fellowship with God had a limit placed on it already. Whatever you would become has its genesis or foundation in this. Even If there is a call of God on your life, the path to the discovery of it would still have to be through the living in the obedience to His Word or principles.
Thus the admonition: start practicing this now.
a. Let the Word of God be part of your life, that is, live the Word—let it be the principles that guide your life and direct you in all you do:
22 BUT BE DOERS OF THE WORD, AND NOT HEARERS ONLY, DECEIVING YOURSELVES. 25 BUT HE WHO LOOKS INTO THE PERFECT LAW OF LIBERTY AND CONTINUES IN IT, AND IS NOT A FORGETFUL HEARER BUT A DOER OF THE WORK, THIS ONE WILL BE BLESSED IN WHAT HE DOES" (James 1:22,25 NKJV).
b. Obey the specific instructions placed in your heart to follow or do. Obedience to these specific instructions are always used as the yardsticks with which to know your obedience to Him, God, and It determines the place you have in His heart, and whatever He would do for you: "BY FAITH ABRAHAM OBEYED WHEN HE WAS CALLED TO GO OUT TO THE PLACE WHICH HE WOULD RECEIVE AS AN INHERITANCE. And he went out, NOT KNOWING WHERE HE WAS GOING" (Hebrews 11:8 NKJV).
READ: Genesis 22:1-3,11-18
Peace.