The time of the new heaven and the new earth is one in which "there shall be no more death, nor sorrow, nor crying; and there shall be no more pain, for the former things have passed away" (Revelation 21:4). The "former things" are the sins and their consequences that caused so much death, sorrow, crying, and pain on earth!
Jesus Christ suggests that behavior and character matter when He says in verse 7, "He who overcomes shall inherit all things." What does a Christian overcome but his own sin, this present evil world, and the Archenemy, Satan the Devil!
Who will be there and who will not? These two chapters make it quite plain: "Blessed are those who do His commandments, that they may have the right to the tree of life, and may enter through the gates into the city [of New Jerusalem]. But outside are dogs and sorcerers and sexually immoral and murderers and idolaters, and whoever loves and practices a lie" (Revelation 22:14-15; cf. 21:8). It is extremely difficult, if not impossible, to deny that God says those who live upright lives will enter His Kingdom and those who live sinful lives will not. Righteous behavior and character certainly do matter to God!
We can go to no higher source to receive the answer to "Does our behavior have eternal value?" than to Jesus Christ Himself. A man came to Him and asked him this very question: "Good Teacher, what good thing shall I do that I may have eternal life?" His answer is unambiguous: "If you want to enter into life, keep the commandments" (Matthew 19:17). The commandments are a code of behavior that builds godly character in those who keep them, and God wants only those with godly character—character like His Son's—in His Kingdom.
Behavior matters. Character matters. The Ten Commandments matter. They will not "pay our way" into God's Kingdom, since God's salvation is a free gift, and it is humanly impossible to purchase or earn it (Romans 6:23; Ephesians 2:8). Nonetheless, when God judges us "according to [our] deeds" (Romans 2:5-11; cf. I John 2:28-29), the record of our behavior will make the difference between eternal life and eternal death.
