Every apologist knows the passage by heart:
1 Peter 3:15 but sanctify Christ as Lord in your hearts, always [being] ready to make a defense to everyone who asks you to give an account for the hope that is in you, yet with gentleness and reverence; (NASB)
But did you know this passage identifies Jesus as YHWH? Note the Greek of the first portion of this passage:
ku,rion de. to.n Cristo.n a`gia,sate evn tai/j kardi,aij u`mw/n(
Now, compare the Greek of the Septuagint (LXX) at Isaiah 8:13:
ku,rion auvto.n a`gia,sate kai. auvto.j e;stai sou fo,boj
See the similarity? Except when Peter draws from the LXX here, he inserts “Christ,” saying we should sanctify, or set Him apart, as “Lord” in our hearts, the term “Lord” in the LXX referring directly to “Yahweh of hosts” in the Hebrew. It is hard for modern readers to climb back into the mindset and context of someone like Peter and hence to feel the weight of the use of such language of Christ, the Messiah. One thing is for sure, the early Christians did not view Jesus the way so many in our culture, and sadly, in “the church,” view Him today.