Our Lord has told us what is important to Him. It is simply showing compassion on others. We usually think compassion is just feeling sorry for someone; however, God has shown us with concrete examples from His Word - the Bible, of what compassion is. Compassion should go one step farther than just feelings; it should do something instead of just desiring to do something. That is what compassion does: something. The “least of them” is not necessarily a “believer” but could be someone who doesn’t even know the Lord yet. It’s like “who is my neighbor?” in the story of the Good Samaritan.
Everything you do for others, you are doing for God. Every act of kindness, every act of charity, every act service is something you will be rewarded for by your Heavenly Father. Everything you do on Earth for others is something God considers that you are doing for Him. You are the hands and feet of our Lord and Savior. Let Him use you today.