Does not persistence in supplication and humbleness before God contradict God's description as "the Most Generous" who gives before being asked?

There is a distinction between dealing with God and dealing with creation. God loves to be asked and to be implored through supplication. Supplication is a great act of worship and a sign of humility and dependence on God. He has warned those who abandon supplication out of arrogance. As for created beings, they become weary of frequent requests. Delaying the answer does not contradict God's generosity, due to His wisdom and His knowledge of the welfare of His servants.