Remote Island Tribesmen Kill Visiting American

Yes, a little wisdom would have been helpful, also an armored vehicles which would have deflected the arrows.

Somehow however their language would have to have been learned so that while driving in the vehicle an audio system could have been used to teach them a few basics.

 

The prophecy was fulfilled before the NT was completed:

14 And this gospel of the kingdom shall be preached in the whole world for a testimony unto all the nations; and then shall the end come.
34 Verily I say unto you, This generation shall not pass away, till all these things be accomplished. Mt 24

So belief cometh of hearing, and hearing by the word of Christ. But I say, Did they not hear? Yea, verily, Their sound went out into all the earth, And their words unto the ends of the world. Ro 10:17-18

5 because of the hope which is laid up for you in the heavens, whereof ye heard before in the word of the truth of the gospel,
6 which is come unto you; even as it is also in all the world bearing fruit and increasing, as it doth in you also, since the day ye heard and knew the grace of God in truth;
23 if so be that ye continue in the faith, grounded and stedfast, and not moved away from the hope of the gospel which ye heard, which was preached in all creation under heaven; whereof I Paul was made a minister. Col 1:23

25 Now to him that is able to establish you according to my gospel and the preaching of Jesus Christ, according to the revelation of the mystery which hath been kept in silence through times eternal,
26 but now is manifested, and by the scriptures of the prophets, according to the commandment of the eternal God, is made known unto all the nations unto obedience of faith: Ro 16