I believe that God's will is supreme. I believe that our free will is subservient to His will. However, I also believe we should not discount the reality of various perspectives different lives contain, who do operate in a free will (that I believe falls, whether they will it or not, in line with His).
Just like the relationship between Divine will and free will, I believe one's limited perspective is subservient to His complete perspective. However, in responding to His selection, we are not stripped of having a personal perspective (one that cannot possibly grasp the fullness of His).
In a general sense, we have not been shown the hearts of others, those He has chosen and those He has not. All we can know is our own (of course, He chooses as He will, and such are the gifts of prophecy and words of knowledge). Thus, we must, when speaking to another (whether believer or unbeliever), approach with an understanding and respect of and for their perspective.
I don't think we deny the supremacy of His complete will and ultimate perspective when we are slow to speak and quick to listen to another whom we believe is off in their beliefs. Rather, we deny our own limited perspective and will, and demonstrate a Divine patience, a marvelous fruit of the Spirit, which in itself might just be the biggest sign of the Kingdom in these last days.
I have faith that God will give us the proper words for the proper person. It is His Divine will and ultimate perspective that can illuminate to us the doorways into the free wills and limited perspectives of those around us (if He so wills for you to reach into a particular individual's life and become a part of ministering to the response of God's selection).
Those who He has chosen to respond to us will, those He had not, will not. (And it must be seen as entirely possible that they will respond to Him, in time, just not, and maybe never, to you.) Therefore it is my heart that we should serve the Divine will, by honoring and respecting the free wills and limited perspectives of those He has created.
Now, one might ask, "Why doesn't He just reveal the hearts of the elect to us now?" And my answer would be, "Who can know?" I believe He has chosen what He has chosen, how He has chosen it. As it is, no one could sound as anything more than an eloquent five year old in these matters. We are so limited in what we can fathom.