Webster says an ambassador is an official of the highest rank who represents his government in the capitol of another country.
The Who: realizing who we are - priviledged persons with fullrights as heirs, loved as children (chosen according to foreknowledge, sanctified by the Spirit, desired for obedience, worthy of His blood) We are of the highest rank, worthy of the responsibility bestowed upon us.
The What: Representitives of our government (namely, Christ). We are to give a proper view of who He is and what He has done. An advocate of the grace we've received to promote to others the quality and richness of that which we've been given.
The Where: In the capitol of another country - well, we definitely are not "home" (meaning heaven) - we we are in a foreign country, but "capitol" strikes me as a dominate place, a place of influence. Not necessarily meaning that we have to move to a big city, but that we not hide in the shaddows - we need to place ourselves in areas so as to have influence and impact on those around us.
The final question is the How: 1 Peter chp. 1 goes on to talk about being holy.
1) Prepare your minds for action
2)Be self controlled
3)Set your hope fully on the grace to be given you.
vs. 14-16 - as obedient children, do not conform to the evil desires you had when you lived in ignorance. But just as he who called you is holy, so be holy in all you do. For as it is written: "Be holy because I am holy." (I think that's reason enough )