You must be baptized to be saved.  How do I know.  I know it because Jesus said so.

Mark 16:16 (ESV)
¹⁶  Whoever believes and is baptized will be saved, but whoever does not believe will be condemned.

If we cannot believe Jesus, who can we believe?

While baptism is necessary for salvation, just because you are baptized does not guarantee that you will make it to heaven.  There have always been those who think that once they are saved, they will go to heaven no matter how they live.  The saints at Corinth were some of the first ones to feel this way.   In the first twelve verses of 1 Corinthians 10, Paul exposed their fallacy with these culminating words.

1 Corinthians 10:12 (ESV)
¹²  Therefore let anyone who thinks that he stands take heed lest he fall.

In baptism, our sins are washed away by the blood of Christ, allowing us to walk in the newness of life (Romans 6:4), but it is up to us, with the help of God (Ephesians 6:10-18) and the strength of Christ (Colossians 1:11), to stay on course.  We can do it because God has given us all the tools necessary to live a victorious life.

2 Peter 1:3 (ESV)
³  His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence,

We have not been called to fail, but to succeed by obtaining glory and excellence by the power of God.  The divine power that Peter is speaking of here is the gospel of Christ (Romans 1:16).  It teaches us everything we need to know to thrive in Christ, including how to “renounce ungodliness and worldly passions, and to live self-controlled, upright, and godly lives” (Titus 2:11-12), but we must do our part.  If we are to prevail in Christ, we must diligently add to our faith (2 Peter 1:5-7).  If we do this, Peter tells us that we will never fall (ver. 10).

Do not let pride get the best of you.  Having a healthy portion of humility is the best way to stay on track spiritually.  Peter said, “Humble yourselves, therefore, under the mighty hand of God so that at the proper time He may exalt you” (1 Peter 5:6).  Have the humility to know that you can stumble and fall, and take the proper measures necessary to prevent it.  Study the Word of God regularly ( 2 Timothy 2:15).  Pray without ceasing (1 Thessalonians 5:17).  Remain an active member of the church, doing your part to edify the body (Ephesians 4:16).  Live like Paul and keep on pressing toward the goal for the prize of heaven (Philippians 3:13-14).

No, baptism will not assure you that you will make it to heaven, but it puts you on the right track.  Once you are saved, no one can take your salvation away, not even the devil.  He can tempt you, but he can never force you to fall away from Christ.  As Jesus said, no one can snatch us out of His hands (John 10:28).  We can, however, voluntarily give up our salvation.  Determine that you will never do this.  Be faithful until death, and Jesus will give you a crown of life (Revelation 2:10).

As you wind down for the night, think about these things.