"And things under the earth"

Philippians 2:10 In the New King James Version says, "That at the name of Jesus every knee should bow of those in heaven, and of those on earth, and of those under earth" it is significant that the NKJV uses the word "those" instead of "things" because we are talking about people in this passage. Those who are able to bend their knee before Jesus. This really helps us to understand what "under the earth" means in this context. It is speaking of people who are under the earth, that is, those who have died and have been buried. This is the simple meaning of this text, however, lets bring in a few more passages to support this idea.

In Matthew 12:40, Jesus said, "for as Jonah was three days and three night in the belly of the great fish. So will the Son of Man be three days and three night in the heart of the earth." Jesus describes His being "in the heart of the earth" for three days and three night. This was a reference to Jesus burial in the tomb. Jesus burial is a significant part of the gospel according to 1 Corinthians 15:4 look also at Revelation 5:3. "and no one in heaven or on earth or under earth was able to open the scroll or to look at it." The point of this passage is that no one alive or dead could open this scroll. Those "under the earth" are the dead.

Then also notice Revelation 5:3, which says, "and every Creature which is in heaven and on the earth and under the earth and such as are in the sea, and all that are in them, I heard saying 'Blessing and honor and glory and power be to Him who sits on the throne, and to the Lamb, forever and ever! Saying in this way includes everyone who had ever lived, lives, or ever will live. Those who are "under the earth" are those who have lived and are now dead. So, when Philippians 2:10 says that every knee shall bow, including those who are under the earth, the expression has reference to those who are dead.

That those who are presently dead will one day bow to Christ means that they will be raised from the dead. Jesus said in John 5:28-29,  Do not marvel at this; for the hour is coming in which all who are in tbe graves will hear His voice and come forth-those who have done good, to the resurrection of the life, and those who have done evil. To the resurrection of condemnation."

We need to be prepared to bow the knee, our knee to Jesus. It is better to do that while we are in this earthly kingdom as we lived our life. In the same context Jesus said. 

Most assuredly, i say to you, he who hear my word and believe in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death into life. Most assuredly i say to you, the hour is coming, and now is, when the dead will hear the voice of the Son of God; and those who hear will live for as the father has life in Himself, so. He has granted the Son to have life in Himself. And has given Him authority to execute judgment also, because He is the Son of Man (John 5:24-27).

When we believe in Jesus and trust Him by obeying Him, He will save us and we will be delivered out of condemnation Let's listen to the voice of Jesus and obey Him presently so that we may not be condemned.