Deuteronomy 1:39
Moreover your little ones, which ye said should be a prey, and your children, which in that day had no knowledge between good and evil, they shall go in thither, and unto them will I give it, and they shall possess it. Moreover your little ones, which ye said should be a prey, and your children, which in that day had no knowledge between good and evil, they shall go in thither, and unto them will I give it, and they shall possess it.
The generation of adults who came as an army out of Egypt was refused entrance into the promised land because they did not wholly follow the Lord but rebelled in disobedience after the report of the spies. The little ones and children of the verse are those whom their parents said and feared would become a prey and who in that day had no knowledge between good and evil. Those children were spared from that judgment. They would go in there, God would give the land to them, and they would possess it.
God's promises, including the promise of the land, are upon condition of obedience. The chapter containing the verse is the Lord's words to be read in full. It is written for admonition upon those on whom the ends of the world are come. It calls them to learn God's word and to appreciate and obey His voice in self-denial and perfection of character rather than holding to human opinion and judgment.