The only mention of grandfather or grandmother in KJV is 2 Timothy 1:5
When I call to remembrance the unfeigned faith that is in thee, which dwelt first in thy grandmother Lois, and thy mother Eunice; and I am persuaded that in thee also.
Verses which contain "children's children." Note the impact of a grandparents actions on his children's children. Blessings or curses.
Genesis 45:10
And thou shalt dwell in the land of Goshen, and thou shalt be near unto me, thou, and thy children, and thy children's children, and thy flocks, and thy herds, and all that thou hast:
Deuteronomy 4:25
When thou shalt beget children, and children's children, and ye shall have remained long in the land, and shall corrupt yourselves, and make a graven image, or the likeness of any thing, and shall do evil in the sight of the LORD thy God, to provoke him to anger:
2 Kings 17:41
So these nations feared the LORD, and served their graven images, both their children, and their children's children: as did their fathers, so do they unto this day.
Psalm 103:17
But the mercy of the LORD is from everlasting to everlasting upon them that fear him, and his righteousness unto children's children;
Psalm 128:6
Yea, thou shalt see thy children's children, and peace upon Israel.
Proverbs 13:22
A good man leaveth an inheritance to his children's children: and the wealth of the sinner is laid up for the just.
Proverbs 17:6
Children's children are the crown of old men; and the glory of children are their fathers.
Jeremiah 2:9
Wherefore I will yet plead with you, saith the LORD, and with your children's children will I plead.
Ezekiel 37:25
And they shall dwell in the land that I have given unto Jacob my servant, wherein your fathers have dwelt; and they shall dwell therein, even they, and their children, and their children's children for ever: and my servant David shall be their prince for ever.
GRANDPARENTS IN THE BIBLE
Cain, the murderer was great, great, great grandpa to Lamech, the murderer.
Seth (Godly Abel's substitute), great, great, great grandpa to Enoch, who "walked with God" (Genesis 5:24), and Enoch was great grandpa to Noah, who "walked with God." (Genesis 6:9)
Ham, cursed by Noah (Genesis 9:24), and grandpa of Nimrod, first king of Babel & Shinar (eventually to become Babylon)
Shem, blessed by Noah (Genesis 9:26), 7 greats grandpa to Abraham, blessed by God (Genesis 12:1-3)
Jacob, blesses his grandchildren, specifically Joseph's sons, effectively giving Joseph a double portion of his inheritance, a privilege traditionally reserved for the firstborn, in Genesis 48. (Jacob was himself a younger brother who got the firstborn blessing, by the way)
Joseph, was blessed to see (and teach?) his great grandchildren (Genesis 50:23).
Jethro, gave wise advice to his grandchildren's father, his son-in-law, Moses (Exodus 18:17).
Rahab, prostitute, great, great grandma to King David, and 28 generations later, (or 30 greats grandma) Jesus
Ruth, foreigner, great grandma to King David, and 28 generations later, (or 29 greats grandma) Jesus
QUESTION TO CONSIDER: How are the decisions we are making today going to affect our grandchildren?
BAD NEWS - Iniquity of the fathers upon descendants to 3rd and 4th generation
Exodus 34:7
Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth generation.
GOOD NEWS - God can break the curse, if we choose to love him. And God's mercy is to a thousand generations of them that love him.
Deuteronomy 7:9
Know therefore that the LORD thy God, he is God, the faithful God, which keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations;