Acts 10:15b: "Do not call anything impure that God has made clean."
Peter was being asked to embrace the Gentiles. They, for most or all of Jewish history, were considered unclean, unworthy of God's favor. Among many things, Jews were not permitted to marry them and, in Peter's time, were not even to enter their houses.
Peter was now, not only being asked to interact with them, but to love them, embrace them, accept them as "clean", and this was before God changed their lives forever,
They were still Gentiles. They still did not truly know God, had not accepted his plan of salvation for them. They were still as they were. Nothing had changed except Peter's attitude toward them and that opened a door for God to do something miraculous. These Gentiles, formerly considered "unclean" and unworthy of God's attention, were now filled with the living, holy Spirit of God, even before they were baptized! (vs 44-48)
Who do I consider unclean? Who do I feel, maybe deep down inside where I might not even admit it, who do I feel does not deserve God's favor or attention? Who is God asking me to notice, to love, to embrace?
Lord God, open my eyes, soften my heart. Help me see, help me love. Purify my heart and refine my attitude so that I may never disdain or reject any that you love and have called me to show your love to.