He who takes a pledge from his fellow does so for one of three reasons a. lest the fellow becomes impoverished and unable to repay him, b. lest he is tightfisted with what he has, making it impossible to collect from him, or c. out of fear that his fellow may die or disappear.
The pledge is the cure for these ills in human relationships, but if people were safe from these three risks in their relationships with others, it would undoubtedly be shameful for them to demand a pledge. Now these three concerns are totally inapplicable to the Creator. May He be exalted. Hence it is much more shameful and absurd to demand a pledge from Him.