31 “Or suppose a king is about to go to war against another king. Won’t he first sit down and consider whether he is able with ten thousand men to oppose the one coming against him with twenty thousand? 32 If he is not able, he will send a delegation while the other is still a long way off and will ask for terms of peace. 33 In the same way, those of you who do not give up everything you have cannot be my disciples." (Luke 14:28-33 NLT)
You don't buy a new car or a house before you figure out if you can afford it. If you don't, you could up lose the house of the car because you could not pay for it.
Jesus tells us to count the cost before following Him. He wants us to be all in on Him because He went all in for us. He died on the cross for us so that we could be forgiven and free to follow Him. Following Jesus means listening to and trusting Him. Jesus promises us forgiveness and eternal life. There is a cost for not following Him. We don't want to go down that road.