The theif on the cross didn't get water baptized so according to the way you Interpret scripture line upon line precept upon precept,here a little there a little the thief on the cross was not saved because he didn't get water baptized and that's error.
Apparently, you need help with what Isaiah actually said as well.
Isaiah chapter 28
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9] Whom shall he teach knowledge? and whom shall he make to understand doctrine? them that are weaned from the milk, and drawn from the breasts.
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10] For precept must be upon precept, precept upon precept; line upon line, line upon line; here a little, and there a little:
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11] For with stammering lips and another tongue will he speak to this people.
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12] To whom he said, This is the rest wherewith ye may cause the weary to rest; and this is the refreshing: yet they would not hear.
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13] But the word of the LORD was unto them precept upon precept, precept upon precept; line upon line, line upon line; here a little, and there a little;
that they might go, and fall backward, and be broken, and snared, and taken.
IN CONTEXT, those to whom "the word of the LORD" was "precept upon precept, precept upon precept; line upon line, line upon; here a little, and there a little" were those who were going to "go, and fall backward, and be broken, and snared, and taken", so Isaiah was NOT presenting this principle in a positive manner. Instead, CONTEXTUALLY, Isaiah was referring to those Israelites/Jews who were going to refuse "the rest" wherewith God was going to "cause the weary to rest" or the "refreshing" which Christ would bring, and this was directly related to the "stammering lips and another tongue" wherewith God would "speak to this people".
IN FACT, Paul quoted this verse in the New Testament in relation to the gift of tongues:
I Corinthians chapter 14
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21]
In the law it is written, With men of other tongues and other lips will I speak unto this people; and yet for all that will they not hear me, saith the Lord.
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22] Wherefore tongues are for a sign, not to them that believe, but to them that believe not: but prophesying serveth not for them that believe not, but for them which believe.
With such being the case, I would heartily recommend that you repent of this erroneous belief of yours as well.