Psalm 116:16 Truly I am your servant, Lord; I serve you just as my mother did; you have freed me from my chains.
It is not just because God created us that we should be counted as His, never mind His servants.
It is because of what Christ has done for us by giving His life for us and then rising from the dead to defeat the curse upon mankind that we should be counted as His.
He has broken us free from the debt we owe due to our issues and our sins. He has broken us free from eternal death and has given us eternal life – as long as we do choose to take it!