When Zechariah regains his voice he bursts out in praise for God and prophesies by the Holy Spirit (v67). Referring to Jesus, he explains what God has done and how He, God/Messiah, has come to redeem his people. He then tells us that God has come …
to show mercy to our ancestors
and to remember his holy covenant…
Luke 1: 72
The ancestors Zechariah refers to are probably not those who are still living, but the dead.
This is an important point because one of the questions I hear asked now and then is, “What about those people who were alive and then died before Jesus came?”
Q: What do you think? Does the redeeming power of Christ extend to all those who died before he came to earth?
Yes, for all those who had faith in God.
Yes, absolutely. All are saved by faith (Romans 4: 1 – 5). A few interesting and related verses would be John 12: 36 – 41 (especially verse 41); John 8: 56; Romans 3: 24 – 25.