This argument is surely one of the oldest (and less weighty) arguments among the "Faith Only"/Charismatic/Holy Roller crowd. Incidentally, how do you KNOW he wasn't baptized?? How do you KNOW he didn't hear one of Jesus' sermons and ran off to be baptized?
Conversation between God and "Try One":
God: Why did you not heed my commandment to be baptized for the remission of your sins? Did you not hear Me when I said to be born again with water AND the Spirit?
Try Again: But...but..but...the thief on the cross!!! He wasn't baptized, and yet you saved him!
God: And just who nailed YOU to a cross??
"Back to Eph. 2: 8,9: " For by grace you have been saved through faith; and that not of yourselves, it is the gift of God; not as a result of works, so that no one may boast."
1 John 2:3-4 (MKJV)
3) And by this we know that we have known Him, if we keep His commandments.
4) He who says, I have known Him, and does not keep His commandments, is a liar, and the truth is not in him.
Now, this clearly shows how we know whether or not we know Christ - if we keep His commandments. This passage makes it quite clear that people who don't keep His commandments are liars, and the truth is NOT in them. Liars won't be in Heaven. There is no way that a person can make it to heaven by faith only, for if they have faith only, and don't keep his commandments, they are liars and have a dead faith (James 2).
Matt. 25: 41-46 (MKJV)
41) Then He also shall say to those on the left hand, Depart from Me, you cursed, into everlasting fire prepared for the Devil and his angels.
42) For I was hungry, and you gave Me no food; I was thirsty, and you gave Me no drink;
43) I was a stranger and you did not take Me in; I was naked, and you did not clothe Me; I was sick, and in prison, and you did not visit me.
44) Then they will also answer Him, saying, Lord, when did we see You hungry, or thirsty, or a stranger, or naked, or sick, or in prison, and did not minister to You?
45) Then He shall answer them, saying, Truly I say to you, Inasmuch as you did not do it to one of the least of these, you did not do it to Me.
46) And these shall go away into everlasting punishment, but the righteous into everlasting life.
It's quite clear that Christ sent these people to Hell for their lack of good works. The root of the problem is their faith - it didn't include obedience to Chist's commandments, which in this case, was to love one another. If they truly loved one another, they would have administered to those people with good works on not been cast into hell. Faith produces good works, because we have faith in Him and we love Him. But the Bible makes it quite clear that if you love Chrsit, then He expects you to keep His commandments (John 14:15), and that he who claims to know Christ and does not keep His commandments are liars, and the truth is not in them (1 John 2:3-4). This goes hand in hand with what the apostle James speaks of in chapter 2 - that faith without works is dead. Faith only doesn't cut the mustard.