This is he who came by water and blood—Jesus Christ; not by the water only but by the water and the blood. And the Spirit is the one who testifies, because the Spirit is the truth. For there are three that testify: the Spirit and the water and the blood; and these three agree. If we receive the testimony of men, the testimony of God is greater, for this is the testimony of God that he has borne concerning his Son. Whoever believes in the Son of God has the testimony in himself. Whoever does not believe God has made him a liar, because he has not believed in the testimony that God has borne concerning his Son. And this is the testimony, that God gave us eternal life, and this life is in his Son. Whoever has the Son has life; whoever does not have the Son of God does not have life.
—1 John 5:6-12
by: Margaret Taylor.
No one has a problem believing me when I tell them who my parents or my siblings are. Those who know them don't even have to ask. The facts are obvious.
People might have a harder time accepting my two oldest grandsons as ours because of their features and their ages. Nonetheless, they are our grandchildren, and there are adoption papers to prove it.
The credentials for your adoption into God's family are found in the Word of God and in the testimony of his indwelling Holy Spirit. Would you still doubt it?