Deuteronomy 4:39 in the King James Version
Know therefore this day, and consider it in thine heart, that the LORD he is God in heaven above, and upon the earth beneath: there is none else.
Context
38 to drive out nations from before you greater and mightier than you, to bring you in, to give you their land for an inheritance, as it is today.
39 Know therefore today, and take it to heart, that the LORD himself is God in heaven above and on the earth beneath. There is no one else.
40 You shall keep his statutes and his commandments which I command you today, that it may go well with you and with your children after you, and that you may prolong your days in the land which the LORD your God gives you for all time.