Some who defend the mid-Acts position say that "because Christ is the head of the church present in the book of Acts and is also the head of the church that is mentioned by Paul from prison that we cannot assume any fundamental difference between these two companies" -- I am quoting because I don't believe their assumptions are correct nor do I believe their conclusions are correct.
When I began my christian life at the age of 21 in a small Baptist chuch in rural New Zealand I knew little of the bible and even less of its doctrine. I knew that I was saved by grace and that was a huge step from darkness to light, while not a library of knowledge it at least found me secure in the beloved.
"This know also, that in the last days perilous times shall come. For men shall be lovers of their own selves..." 2 Timothy 3:1-2
The prevailing sign of the "last days" will be a misplacement of love. The love of man will far exceed the love of God and His Son. The love of man will far exceed one's love for integrity truth, righteousness and holiness. In fact, statements in favor of the truth are now proclaimed as "hate speech" in many quarters.
The book of Ephesians is the high water mark of PAul's prison ministry. It relates to us both the circumstances and content of the revelation of "the mystery" which was hid in God. All saints immediately prior to this revelation believed and held to the hope which was proclaimed to them in the Acts and therefore would need to be adjusted to the new and unprophesied hope that was now their's by grace.
Eph 3:8 Unto me, who am less than the least of all saints, is this grace given, that I should preach among the Gentiles the unsearchable riches of Christ;
Eph 3:8 (TR) εμοι τω ελαχιστοτερω παντων των αγιων εδοθη η χαρις αυτη εν τοις εθνεσιν ευαγγελισασθαι τον ανεξιχνιαστον πλουτον του χριστου
The greek word translated "unsearchable" is the adjective ἀνεξιχνίαστος which is found here and in Rom. 11:33 where it is translated "past finding out".
Eph. 6.15 (AV) And your feet shod with the preparation of the gospel of peace;
Eph. 6.15 (TR) και υποδησαμενοι τους ποδας εν ετοιμασια του ευαγγελιου της ειρηνης
"Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days: Which are a shadow of things to come; but the body is of Christ." Colossians 2:16-17
We have just finished the Book of Colossians in our weekly Bible study. The book was written by Paul during his first imprisonment in Rome after he announced to the chief of the Jews:
It's resurrection time again!
"Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee. But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas: For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth." Matthew 12:38-40
Have you noticed that today's "Messianic synagogues" are made up mostly of Gentiles, not Jews? Among some Christians there is the thinking that to partake of Jewish feasts, Jewish rituals, Jewish days and Jewish attire makes one more spiritual than a Gentile in a New Testament church. Even in the future Smyrna church during the tribulation period there will be people claiming to be Jews who are not (Revelation 2:8-10.)
Israel, today, is "Lo-ammi" (Hosea 1:9) meaning not My people. Israel's condition is described in Hosea 3:4: