But when the goodness and loving kindness of God our Savior appeared, He saved us, not because of works done by us in righteousness, but according to His own mercy, by the washing of regeneration and renewal of the Holy Spirit, whom He poured out on us richly through Jesus Christ our Savior, so that being justified by His grace we might become heirs according to the hope of eternal life. ~ Titus 3.4-7
Herein lies the second reason we must be born again in obedience to Jesus' command. That reason? We can't save ourselves. We need a whole new life, external to ourselves, imparted to us through some means outside of what we can manage or manipulate. We must be born again.
He saved us according to His mercy. We couldn't work and do and try and try again and try again and try again and try again and make a promise and try again. That's the treadmill of religion: you get tired without going anywhere. The reason God doesn't accept our works of righteousness in the salvation equation is because it's an affront to Jesus. If Jesus needs my work added to His work on the cross, then His work really wasn't complete and He lied when He triumphantly cried, "It is finished." So you can't add baptism, giving, praying, Bible reading, helping little old ladies cross the street or anything else to improve your chances with God. Those things come after you receive His salvation because you live in obedience to the One who saved you, fulfilling your role as an heir of the hope of eternal life. Works aren't the cause of your salvation but the result of it.
You must be born again. Think about this: the only thing you did when you were born the first time was show up and cry. It's a pretty similar situation on being born again.
But that's just me thinking thoughts...