The place of the scripture which he read was this, He was led as a sheep to the slaughter; and like a lamb dumb before his shearer, so opened he not his mouth:
Note 6 at Ac 8:32: The Lord led Philip right to a man who was reading some of the classic Old Testament scriptures about the Christ (Isa 53:7-8) and wondering who the prophet was speaking of. There could not have been a better situation for witnessing about Jesus. It is wonderful when the Holy Spirit leads us into situations like this, where His guidance is so obvious.
However, it is just as true that the Lord will lead us to speak to those who are not this receptive, because He loves them too. We may not always be led to people like this eunuch, but that does not mean that the Lord has not directed us to speak to them.