"The Spirit Himself bears witness with our spirit, that we are the children of God" (Romans 8:16).
He who has the Spirit of God in himself - only he has the witness that he is the child of God. Without the Spirit of God there is no such witness. Not even the entire universe can give this witness. The universe, alone, without the Spirit of God - what else does it witness to us other than that we are its slaves, its victims, which it unmercifully swallows? In essence, the pagans thought that also.
The opponents of God today, do they not think likewise? They do think so. For indeed, it is difficult to take that thought away from man who did not recognize the Spirit of Christ, the Spirit of God, the Witness of Heaven. The same apostle says: "For you have not received the spirit of bondage" (Romans 8:15). What is this spirit of bondage? It is every other spirit except the Spirit of God, Who Christ the Lord sends to those who love Him. The spirit of bondage is the spirit of materialism, the spirit of fortune-telling, the spirit of naturalism, the spirit of pessimism, the spirit of despair, the spirit of vice. Only the Spirit of God is the All-Holy Spirit of adoption and freedom.
O what happiness, O what peace, O what joy when the Spirit of God cuddles in the cleansed heart of man as a sparrow does in its nest! Then our hope opens hundreds of doors in the prison of the universe and our embrace, wider than the universe, stretches out to the One Who is greater and more merciful than the universe. To Whom? To the Father! And then we cry out: "Abba, Father!" (Romans 8:15).
The witness of God, which comes through the eyes, can even lead us to doubt that we are the children of God. But, the witness which comes to us from the heart, from the Spirit of God, does not leave even the slightest doubt. God witnesses about God. What kind of doubt can there be? God the Holy Spirit caresses us in the heart of our very being. Can there be any kind of doubt there? No; for then we know and feel completely confident that God is the Father and we, the children of God. No one's servants, no one's slaves, rather the children of God.
O Lord God, Holy Spirit come abide in us and remain with us as a Witness of the Trinity and the Kingdom, as a Witness of the immortal Paradise. To You be glory and thanks always. Amen.