"The Spirit itself beareth witness with our spirit, that we are the children of God." (Rom.8:16)
In today's popular vernacular, a "kindred spirit" is someone who is like us in character and temperament. The actual meaning of "kindred," of course, is someone related to us by blood. Either way, you and I, as believers, have a true kindred spirit—the Holy Spirit of God. We often say (and rightly so) that our eternal salvation is based on the Word of God and not our feelings and emotions. But that same Word tells us that if we are truly a child of God, the Spirit of God will bear witness to that fact within us. In other words, we will have an affinity for the same things. I have been conscious of this from the day I was saved to this very hour. I may not have always seen eye-to-eye with my "Kindred Spirit," I'm sorry to say; but I've never doubted that He and I are kin!
In addition, like two people who have lived together for a long time, He often finishes my sentences for me when I'm talking to God. In fact, verse 26 says that when I become tongue-tied in the presence of God, He steps in and articulates my longings and desires. When I am speechless, He speaks up, and when He does, I can be sure that what He says will be "according to the will of God" (v. 27).
And (joy of joys!) verse 11 of Romans 8 promises that if I die before the Lord returns for His own, that same Spirit will "quicken [my] mortal body" and raise it from the dead. Until that day, the two of us will fellowship together (Philip. 2:1), as two friends always do when they are truly kindred spirits.