Zeal - Intensity, Passion
They had a passion for God, but they didn't really know God.
2 Peter 3:17-18 reads "You therefore, beloved, since you know this beforehand, beware lest you also fall from your own steadfastness, being led away with the error of the wicked; 18 but grow in the grace and knowledge of our Lord and Savior, Jesus Christ. To Him be the glory both now and forever. Amen."
This basically lays out your only two options. You can either fall into sin, or get to know Jesus, and if you're in sin, you cannot know Jesus.
John 14:21 ""He who has My commandments and keeps them, it is he who loves Me. And he who love Me will be loved by My Father, and I will love him and manifest myself to Him.""
In order to love Jesus you have to know Him! and it says here that those who keep his commandments, and don't sin, love him, and therefore know him! You can either know Jesus or know sin! Your choice!
Manifest - to make clear or evident to the eye or the understanding; show plainly
Jesus wants to show Himself to us, but first we have to purify ourselves of sin! If we keep out of sin and spend time with Jesus, He will reveal Himself to us!
John 14:6-7 Jesus said to him, "I am the way, the truth, and the life. No one comes through the Father except through Me. 7 "If you had known Me, you would have known my father also; and from now on you know him and have seen him""
The only way we can get to know God is to know Jesus. We get to know Jesus through prayer and by reading his word. You can get to know someone by hearing what they say, and so if we study God's word, which is what he says, then we can get to know him! God will give you new revelations of who he is each time you read the word, allowing you to know him and grow closer to him! The great thing about God is that no matter how much you already know him, there's always more to know!