Psalm 105:1-9
O Give thanks unto the Lord; call upon his name: make known his deeds among the people.

Sing unto him, sing psalms unto him: talk ye of all his wondrous works.

Glory ye in his holy name: let the heart of them rejoice that seek the Lord.

Seek the Lord, and his strength: seek his face evermore.

Remember his marvellous works that he hath done; his wonders, and the judgments of his mouth;

O ye seed of Abraham his servant, ye children of Jacob his chosen.

He is the Lord our God: his judgments are in all the earth.

He hath remembered his covenant for ever, the word which he commanded to a thousand generations.

Which covenant he made with Abraham, and his oath unto Isaac;

Psalm 105:42-45

For he remembered his holy promise, and Abraham his servant.

And he brought forth his people with joy, and his chosen with gladness:

And gave them the lands of the heathen: and they inherited the labour of the people;

That they might observe his statutes, and keep his laws. Praise ye the Lord.

I'm going to spend some time studying a little booklet titled: God's Creative Power for Healing by Charles Capps. In it he shows from the bible how what we believe and what we say affect not only our health, but the systems inside our bodies that keep us healthy. He teaches that first God promised Abraham that he would be the father of many nations, and that Abraham had to hope that promise was attainable before he could believe in it.