Jesus Christ says that because some of His people have been keeping His command to persevere, He will keep them from the worst of what lies ahead. They have already proved their faithfulness to Him; He knows where they stand, He sees their track record with Him, and He will not require them to experience everything that the rest of humanity will suffer.
The word translated "kept" or "keep," used twice, plays into this. This word means "to attend to carefully; to maintain; to guard; to hold fast," and the way that it is used indicates reciprocity. We certainly want God to guard, hold fast, and carefully attend to us. We would prefer that He guard us and hold us fast far away from the destruction and torment that will come upon the world! But the flipside is that He wants us to do the same thing—keep, guard, hold fast—with regard to our responsibilities to the covenant.
In other words, if we want God to take an active interest in our well-being during that time, we should understand the principle of reciprocity and take an active interest in Him at this time. If we diligently guard the things He has committed to our trust, He will do the same for us.
Jesus' brother, James, provides insight into the perseverance that Christ wants us to have: "My brethren, count it all joy when you fall into various trials, knowing that the testing of your faith produces patience. But let patience have its perfect work, that you may be perfect and complete, lacking nothing" (James 1:2-4).
The perseverance that we will increasingly need as the end approaches cannot be developed all at once. Goofing off all semester and then cramming for the final exam rarely works in college, and it certainly will not work where our covenant and relationship with God is concerned. James counsels us to be thankful when our faith is tested, because all of those little exercises of faith not only prepare us for substantial trials, but also make us spiritually complete.
The upshot is that no man, by himself, has the strength to endure and persevere through what lies ahead. Without God, we are all dead men, physically and spiritually, but because "power belongs to God" (Psalm 62:11), we can tap into the source of true strength through our relationship with Him. He decides the circumstances of our lives. He alone knows what we need to survive the trials and temptations at the end. More importantly, He knows what we need to be prepared for eternal life.
Remember that God desires godly offspring (Malachi 2:15). He is creating sons and daughters in His image (Genesis 1:26; Romans 8:29). He is using His perfect creative genius to engineer the experiences and circumstances that we need to take on His image and have His eternal character formed in us.
For some, walking with God through the very depths of the end time is what they will need to become "perfect and complete, lacking nothing." A large part of that may be a result of the choices that they make now, and their tendencies toward apathy, complacency, or compromise.
For others who are already keeping His command to persevere, He will keep them from the hour of trial. It does not mean they will not see hardship: They must see hardship to endure courageously. But because of their constancy under duress—because God is not a stranger, and they are already accustomed to walking through life with Him and drawing upon His strength—they will be given a blessing of protection.