Apparent contradiction versus divine purpose

فَأَرَدْنَآ أَن يُبْدِلَهُمَا رَبُّهُمَا خَيْرًا مِّنْهُ زَكَوٰةً وَأَقْرَبَ رُحْمًا

So we intended that their Lord should substitute for them one better than him in purity and nearer to mercy.