And those who have believed respond to Him, meaning they respond to them. The 'lam' has been omitted as it was omitted in His saying, 'And when they call them.' This means He rewards them for their obedience and increases them in reward as a favor. Or when they call upon Him, He responds to their supplication and gives them what they requested and increases them beyond what they sought. It is said that the response is their action, meaning they respond to Him with obedience when He calls them to it. And He increases them from His bounty beyond their reward. And from Sa'id ibn Jubair: this is from their action: they respond to Him when He calls them. And from Ibrahim ibn Adham, it was said to him: why do we call and are not responded to? He said: because He called you but you did not respond to Him. Then he recited, 'And Allah invites to the Home of Peace and guides whom He wills to a straight path.'