What are the heavenly places / heavenly realms?

from the old testament

• God lives in heaven (Isaiah 63:15; see also Acts 7:55), but the word heaven is also used to describe the generic heavens (the sky or atmosphere mentioned in Genesis 1:1; Psalm 148:4).
• God sometimes sends angels from the heavenly realms to appear on earth, even taking on the form of men, to share messages from Him with specific people (Genesis 18:2, 16–17; 19:1–2; Daniel 9:10–23).
• Satan and his demons live in a different part of the heavenly realms. It's important to note that Satan and the evil spirits that follow him are no match for God and His angels; they are not God's equal opponents in any way but are created beings who have temporary power (Isaiah 14:12; see also Luke 22:31; Revelation 12:12).
• There is a real spiritual battle going on in the spirit realm, and this battle impacts us here on earth. We see an illustration of this in Daniel 10, where we learn that Daniel's angelic messenger was detained by an evil spirit (verse 13).

from the new testament

• Since we live on earth, we have limited knowledge and understanding of the spirit world. What we do know, we learn from the Bible. God Himself is spirit (John 4:24); He is not limited by time and space or physical matter. He is above it all.
• In heaven, God is seated on His throne (Matthew 23:22; Hebrews 4:16), surrounded by worshiping angels (Revelation 7:11; Psalm 99:1).
• The book of Ephesians mentions the "heavenly places" or "heavenly realms" several times (Ephesians 1:3, 20; 2:6; 3:10; 6:12). This is from the Greek word epouranios and here refers to "the sphere of spiritual activities." The spirit realm is a real place, and within the spirit realm are holy spiritual beings, like the angels, as well as evil spiritual beings, like the demons.
• Ephesians 1:20 talks about Jesus being seated in the heavenly realms. God "raised [Christ] from the dead and seated him at his right hand in the heavenly places." Later in Ephesians, however, Paul talks about evil spirits at work within the same realm: "For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places" (Ephesians 6:12).
• The fallen angels, who also live in the heavenly places, are hard at work to destroy God's plans for individuals and the world (see John 10:10). We see the reality of spiritual warfare in passages like Ephesians 6:10–19, 2 Corinthians 10:3–6, and in the book of Revelation.

implications for today

There are a few things to take away from all of this. First, the heavenly realms are real and have spiritual battles taking place. And second, we are not powerless in the fight. God gives us the weapons we need to fight: "For the weapons of our warfare are not of the flesh but have divine power to destroy strongholds" (2 Corinthians 10:4). He gives us the armor we need to stand strong: "Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand firm" (Ephesians 6:13).

As believers, we are empowered by the Holy Spirit to put on our spiritual armor and engage in the battle (Ephesians 6:10–18). We need not fear because God already has the victory (1 John 4:4; John 16:33; Revelation 19–20). We should also remember that, as much as we feel anchored to our lives here on earth, there is an eternal life to come (2 Corinthians 5:1; 1 John 5:11).