This three word title is rather rare in Scripture. The three words are found in close proximity only 15 times in all the Bible. The first instance is in Genesis 17:1 when God told Abram when he was 99 years old that he was making a covenant with him, and He changed his name to Abraham. So, the importance of the scheme of redemption through the lineage of Abraham is connected with the three words, “Lord God Almighty.”
The second time those appear together is in Exodus 6:3 when God talked to Moses about the Israelites leaving Egypt and going to the Promised Land. He mentioned the covenant He had with them. Other instances in the Old Testament are Numbers 24:1–4 (the incident with Balaam), Psalm 68:14–16 (this Psalm was used by David at the moving of the Ark of the Covenant), Psalm 91:1–2 (speaking of protection, refuge, trust and dwelling with Him, and the term Most High appears as well), Ezekiel 10:4–5 (where judgment was pronounced on Israel and Judah) and Joel 1:14–15 (again where judgment was pronounced).
The three word title is used seven times in The Revelation 1:6–8; 4:8 (God on His Throne); 11:17; 15:3; 16:7; 19:15–16 (v. 13 mentions The Word of God) and 21:22. The Revelation concerns Judgment along with God’s abiding care, protection and salvation for the faithful.
The only other instance where the words are used together is 2 Corinthians 6:16–18. It is this text that gives a very good commentary on the probable emphasis to be communicated by the three words used together. From these verses we learn that God dwells with those who are in the temple of God. Those in the temple are not to have agreement with false gods. His followers are to be separate or sanctified (set apart) to Him. God will receive those who do such. He will be a Father to them. So, we see His power, authority and care. Many commentators think “Almighty” refers to His sustaining care. “Lord” denotes His covenant relationship with His followers. “God” denotes His creative power. As the Lord God Almighty, He has the authority to expect obedience and has the power to give judgment on all who follow Him or don’t follow him.
Study your Bible. Learn all you can about our Lord God Almighty. Then, do what you can to obey Him. If any of this is hard to understand, ask an adult to help you.