“So the Jews gathered around him and said to him, “How long will you keep us in suspense? If you are the messiah, tell us plainly.” John 10:24 (NRSV)
In spite of Jesus explaining to the Jews, they don’t care to believe him. They doubted his presence.
It is clear that these Jews had expected their Messiah to fall from Heaven and boldly declare himself. They had not expected a Messiah who was born by a physical being.
For this reason, they doubted.
What I learnt from this verse is simply about FAITH. One does not need to see God in His Splendour before believing He is God. Also one does not need to see Jesus descending down from Heaven believing affirming He is the Messiah.
Your Faith will speak for you. You only need to believe everything the Bible and the Holy Spirit say about God.
Never try to follow the way of these Jews whose spiritual understanding was far from the truth.
And to develop your Faith to that level of Confidence, you must pray every day and at all times and READ the Word of God daily.
This way you will be fully grounded in Faith and won’t doubt the existence of God.