To preface the final example from the book of Acts, recall the following exchange between Christ and the Pharisees. Jesus asked:
MATTHEW 21:24 And Jesus answered and said unto them, I also will ask you one thing, which if ye tell me, I in like wise will tell you by what authority I do these things.
MATTHEW 21:25 The baptism of John, whence was it? from heaven, or of men? And they reasoned with themselves, saying, If we shall say, From heaven; he will say unto us, Why did ye not then believe him?
MATTHEW 21:26 But if we shall say, Of men; we fear the people; for all hold John as a prophet.
The obvious point of this dialog, at least for the purposes of this topic, is that John's baptism was ordained by God. This fact should not be taken lightly!!
Years after that conversation, this happened:
ACTS 18:24 ¶ And a certain Jew named Apollos, born at Alexandria, an eloquent man, and mighty in the scriptures, came to Ephesus.
ACTS 18:25 This man was instructed in the way of the Lord; and being fervent in the spirit, he spake and taught diligently the things of the Lord, knowing only the baptism of John.
ACTS 18:26 And he began to speak boldly in the synagogue: whom when Aquila and Priscilla had heard, they took him unto them, and expounded unto him the way of God more perfectly.
If anyone is willing to listen, it is understood that this Apollos believed, even though it is not specifically stated that he did. Likewise, it is understood that he was baptized, although it does not specifically say that he was.
Immediately after this, however, it does say so, with another group who previously had had similar beliefs to Apollos:
ACTS 19:1 And it came to pass, that, while Apollos was at Corinth, Paul having passed through the upper coasts came to Ephesus: and finding certain disciples,
ACTS 19:2 He said unto them, Have ye received the Holy Ghost since ye believed? And they said unto him, We have not so much as heard whether there be any Holy Ghost.
ACTS 19:3 And he said unto them, Unto what then were ye baptized? And they said, Unto John's baptism.
ACTS 19:4 Then said Paul, John verily baptized with the baptism of repentance, saying unto the people, that they should believe on him which should come after him, that is, on Christ Jesus.
ACTS 19:5 When they heard this, they were baptized in the name of the Lord Jesus.
ACTS 19:6 And when Paul had laid his hands upon them, the Holy Ghost came on them; and they spake with tongues, and prophesied.
These men had been baptized with the baptism of John. (John's baptism was, in fact, ordained by God, unlike so many heretical baptisms of today, which are after the traditions of men, and not after Christ. Such baptisms of today, like the baptisms of the disciples of Acts 19:1-7 were done in ignorance, not malice.) Nevertheless, when these disciples heard the word of the Lord, they were re-baptized "in the name of the Lord Jesus."
Why is it written that they spoke with tongues? Among other reasons, it was so that we today would believe! As Paul elsewhere wrote:
1 CORINTHIANS 14:22 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.
16.1.1 It can be deduced that Apollos (from Acts 18:24-28) was re-baptized in the name of Jesus Christ, even though it never specifically says that he did. This deduction can be made through biblical precedent of those who were saved (section 7 and section 14, above). Likewise, it can be deduced that he actually believed, even though it never specifically says that he did that either. This too can be deduced through biblical precedent of those who were saved (they all believed).
16.1.2 Likewise, it can also be deduced, both through precedent and through immediate context, that the twelve of Acts 19:1-7 believed on Christ Jesus, even though the scripture never actually says that they did.
16.1.3 In those days, it was understood that the disciples of Christ had each been baptized in water. At Acts 19:3, upon hearing that these disciples of John the Baptist had not received the Holy Ghost, Paul asked: "Unto what then were ye baptized?" He did not ask "Have you been baptized," he asked "Unto what then were ye baptized," the presumption being that they had been baptized unto something.
16.1.4 Water baptism is done in the name of "Jesus Christ," or in some variation of His name. In this case, it specifically says at Acts 19:5 that they were baptized "in the name of the Lord Jesus." It has been previously established in section 6 that nobody was ever baptized with the words "in the name of the Father, and of the Son, and of the Holy Ghost."
Besides, God doesn't just give the Holy Ghost out to just anyone.