Angels are personal spiritual beings who have intelligence, emotions, and will. This is true of both the good and evil angels (demons). Angels possess intelligence (Matthew 8:29; 2 Corinthians 11:3; 1 Peter 1:12), show emotion (Luke 2:13; James 2:19; Revelation 12:17), and exercise will (Luke 8:28-31; 2 Timothy 2:26; Jude 6). Angels are spirit beings (Hebrews 1:14) without true physical bodies. Although they do not have physical bodies, they are still personalities and occasionally take on physical bodies.
Because they are created beings, their knowledge is limited. This means they do not know all things as God does (Matthew 24:36). They do seem to have greater knowledge than humans, however, which may be due to three things. First, angels were created as an order of creatures higher than humans. Therefore, they innately possess greater knowledge. Second, the angels know what God's Word says (James 2:19; Revelation 12:12). Third, angels gain knowledge through long observation of human activities. Unlike humans, angels do not have to study the past; they have experienced it. Therefore, they know how others have acted and reacted in situations and can predict with a greater degree of accuracy how we may act in similar circumstances.
Though they have wills, angels, like all creatures, are subject to the will of God. Good angels are sent by God to help believers (Hebrews 1:14). Here are some activities the Bible ascribes to angels:
They praise God (Psalm 148:1-2; Isaiah 6:3). They worship God (Hebrews 1:6; Revelation 5:8-13). They rejoice in what God does (Job 38:6-7). They serve God (Psalm 103:20; Revelation 22:9). They appear before God (Job 1:6; 2:1). They are instruments of God’s judgments (Revelation 7:1; 8:2). They bring answers to prayer (Acts 12:5-10). They aid in winning people to Christ (Acts 8:26; 10:3). They observe Christian order, work, and suffering (1 Corinthians 4:9; 11:10; Ephesians 3:10; 1 Peter 1:12). They encourage in times of danger (Acts 27:23-24). They care for the righteous at the time of death (Luke 16:22).
Angels are an entirely different order of being than humans. Human beings do not become angels after they die. Angels will never become, and never were, human beings. God created the angels, just as He created humanity. The Bible nowhere states that angels are created in the image and likeness of God, as humans are (Genesis 1:26). Angels are spiritual beings that can, to a certain degree, take on physical form. Humans are primarily physical beings, but with a spiritual aspect. The greatest thing we can learn from the holy angels is their instant, unquestioning obedience to God’s commands.