Carol R. Holladay provides the following commentary on Acts 13:48:
Those “[who
had] been destined for eternal life believed,” a heavily predestinarian claim,
may be an allusion to the widespread Jewish notion of being enrolled in God’s
book (See Exod 32:32-33; Ps 69:28; Dan 12:1; 1 En. 47.3; 104.1; 108.3; Jub
30.19-20, 22; Rev 3:5; 13:8; 17:8; 20:12; 21:27). The gift of the meaning seems
to be: Since gentiles have been destined for eternal life by virtue of God’s
ancient (or prior) desire to include them among the people of God, they become
believers. (Carol R. Holladay, Acts: A Commentary [The New Testament
Library; Louisville, Ky.: Westminster John Knox Press, 2016], 282, emphasis added)
This is important as the biblical texts speak
of people having their names blotted out from the book of life, showing that
the contents thereof is not static:
He
that overcometh, the same shall be clothed in white raiment; and I will not
blot out his name out of the book of life, but I will confess his name before
my Father, and before his angels. (Rev 3:5)
Yet
now, if thou wilt not forgive their sin--; and if not, blot me, I pray thee,
out of thy book which thou hast written. And the Lord said unto Moses,
Whosoever hath sinned against me, him will I blot out of my book (Exo 32:32-33)
And it
come to pass,when he heareth the words of this curse, that he bless himself in
his heart, saying, I shall have peace, though I walk in the imagination of mine
heart, to add drunkenness to thirst. The Lord will not spare him, but then the
anger of the Lord and his jealousy shall smoke against that man, and all the
curses that are written in this book shall lie upon him, and the Lord shall
blot out his name from under heaven. (Deut 29:19-20)
Let
them be blotted out of the book of the living, and not be written with the
righteous. (Psa 69:28)
And it
shall come to pass, that he that is left in Zion, and he that remaineth in
Jerusalem, shall be called holy, even every one that is written among the
living in Jerusalem: (Isa 4:3)
We see this in 1 Enoch, too:
As for
you, wait patiently until sin passes away, for the names of (the sinners) shall
be blotted out from the Book of Life and the books of the Holy One; their seeds
shall be destroyed forever and their spirits shall perish and die; they shall
cry and lament in a place that is an invisible wilderness and burn in the
fire—for there exists ground there (as upon the earth). (1 Enoch 108:3)
Further, it should be noted that τεταγμενοι
is better understood as a middle, not aorist, perfect passive participle, as
the Gentiles are the subject of each of the verbs in the verse. Furthermore, it
fits better the context: Luke is contrasting these believing Gentiles with the
Jews who rejected the gospel in v. 45.