Then there is no basis to say that some people will not be saved because God doesn't show them mercy.
9 If you declare with your mouth, “Jesus is Lord,” and believe in your heart that God raised him from the dead, you will be saved. 10 For it is with your heart that you believe and are justified, and it is with your mouth that you profess your faith and are saved. 11 As Scripture says, “Anyone who believes in him will never be put to shame.”[e] 12 For there is no difference between Jew and Gentile—the same Lord is Lord of all and richly blesses all who call on him, 13 for, “Everyone who calls on the name of the Lord will be saved.”[f]
God would be unrighteous if I call on the name of the Lord and then receive eternal damnation. If God is unrighteous his Kingdom will not stand. The Kingdom is built and established on righteousness.