To understand something or someone means to have a clear and complete idea of the subject. God has different personalities He showed to different people depending on the situation involved.
To Moses on Mount Horeb, He was I AM THAT I AM (Exodus 3:14). To the Israelites in Egypt, He showed them that He is the great deliverer (Exodus 14:30). To the Israelites when they fought against the Amalekites, He showed Himself as Jehovah Nissi (Exodus 17:15).
The knowledge of who God is varies among believers because of the level of personal relationship each believer has with Him.
To understand who God is, you need to know Him first and to know Him, you need to spend time with Him. The knowledge of God comes primarily from His word (The Bible), when you know what He said about Himself to people in the Bible. It gives an idea of who He is. It is the knowledge you have of Him that the Holy Spirit expands in your heart to give you a deeper understanding of Him.
To understand who God is, you need to know the truth about Him yourself. Moses had a personal relationship with God so he could say the things he said about Him. Abraham had a personal relationship with God so he could talk to God as a friend.
Your relationship with God is dependent on your understanding of God. You cannot understand God on your own neither can you understand Him primarily by what others say. It is the Holy Spirit that helps you but before He can help you to understand who God is, you need to have an idea, a knowledge of God.
The knowledge you can get about God can come from anywhere but it has to be confirmed in the Word of God by studying it. This is why the Bible says study to show yourself approved (2 Timothy 2:15) as this will help correct any wrong idea. It is what you know you study; and what you study, you understand.
Your understanding of who God is should not be the understanding you get from others, you need to discover God yourself. Acts 11:17 says,
“These were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so”.
You are to check the Word for yourself to have a good understanding of who God is irrespective of who told you what you know about Him. As long as your knowledge is of the Bible, then you should confirm with the Bible. The Bible teaches about God than anyone else. The Holy Spirit helps in explaining the Bible to us and therefore increases our understanding.
What is your understanding of God’s personality based on? Do you truly understand who God is?
Spend more time with Him and get to know Him better by yourself.