Let's make it simple.
The thief on the cross put his faith in Christ.
Jesus said, "Today thou shalt be with me in paradise."
As far as we are concerned he was "saved," but had no chance to do any good works afterward, and certainly wasn't baptized.
The "faith" that he put in Christ was the only "obedience" that Christ required, yet was not a work. Faith is an intangible. It is not something that is measured, or at least accurately measured like one's weight.
The other thief continued to blaspheme Christ. It wouldn't be his bad works of blasphemy that would send him to Hell but his unbelief or rejection of Christ.
Belief or faith in Christ is the only requirement for salvation, for salvation is a gift of God.
Unbelief or rejection of that gift or of Christ is sure damnation.
I agree, the first thief was saved by grace! But the thief was still under the law at the time of his death!
Let me ask you this, Do you believe that Repentance is a part of the Salvation experience or do you just beleive that you have to believe without Repentance?
The theif on the cross was a special example of Gods Grace. Remember the parable of the Householder (Mat 20)?
For the kingdom of heaven is like unto a man [that is] an householder, which went out early in the morning to hire labourers into his vineyard. And when he had agreed with the labourers for a penny a day, he sent them into his vineyard. And he went out about the third hour, and saw others standing idle in the marketplace, And said unto them; Go ye also into the vineyard, and whatsoever is right I will give you. And they went their way. Again he went out about the sixth and ninth hour, and did likewise. And about the eleventh hour he went out, and found others standing idle, and saith unto them, Why stand ye here all the day idle?
They say unto him, Because no man hath hired us. He saith unto them, Go ye also into the vineyard; and whatsoever is right, [that] shall ye receive. So when even was come, the lord of the vineyard saith unto his steward, Call the labourers, and give them [their] hire, beginning from the last unto the first. And when they came that [were hired] about the eleventh hour, they received every man a penny. But when the first came, they supposed that they should have received more; and they likewise received every man a penny. And when they had received [it], they murmured against the goodman of the house, Saying, These last have wrought [but] one hour, and thou hast made them equal unto us, which have borne the burden and heat of the day. But he answered one of them, and said, Friend, I do thee no wrong: didst not thou agree with me for a penny? Take [that] thine [is], and go thy way: I will give unto this last, even as unto thee. Is it not lawful for me to do what I will with mine own? Is thine eye evil, because I am good? So the last shall be first, and the first last: for many be called, but few chosen.
Who am I to judge antoher? God can save anyone anyway he feels! But for us, who have heard the Word of God and know it are held with a much higher accountability! We've (Everyone who put's their trust in Christ) been laboring a little longer and we know a few more things. For a man to know to do good and do it not to him it is Sin (Jam 4:17).
Matt 19:16 And, behold, one came and said unto him, Good Master, what good thing shall I do, that I may have eternal life?
Jesus told him to sell everything he had and follow him, but the rich man could not b/c he had many possissions. It wasn't that the Rich man did not believe in Jesus, (he did or he would not of asked him how) that kept him from salvation but it was his lack of obedience to Christ!
This is just speculation but I beleive that if the Thief on the cross would have continued to live, his obedience would have confirimed his faith in Christ!