Lord, what is man, that You take knowledge of him? Or the son of man, that You are mindful of him? (Psalm 144:3)
Until Christ redeemed us, we were undone and cast off. Nevertheless, God in His mercy and filled with compassion saved us through the One in whom He was very mindful, His Son, Christ Jesus. Now that you are Christ's, God is very mindful of you. His thoughts concerning you are more than the sands of the sea. He is so mindful of you that He sent the Comforter (the Holy Spirit) to keep you and guide you. He says of you, "I will never leave you nor forsake you." I am sure that there are times that we doubt, but we need not. God knows everything there is to know about us. He is always there. He always hears us and He, clearly tells us, "I am with you always, even to the end of the age." Therefore to answer the psalmist's question: We are children of the King. That is why He is mindful of us and knows us so very well.