What is the ruling on saying, "O Lord, You know the rest"?

The supplicant's statement, "O Lord, I will not mention what I desire, for You are more knowledgeable of what I desire," contradicts Allah's command to supplicate and His love for His servant's insistence, as well as the guidance of the Prophet, peace and blessings be upon him. Supplication is not called supplication unless it is uttered. A servant's asking his Lord for his needs is among the best acts of worship, and Allah has commanded it. Abandoning supplication under the pretext of "His knowledge of my state is sufficient for my asking" is a statement that is invalid Islamically.