# Please call to mind

"Please remember" 

# the word you commanded your servant Moses

The pronouns "you" and "your" refer to God and so are singular. 

# If you act unfaithfully ... scatter you

The pronouns "you" and "your" are plural and refer to the Israelite people.

# I will scatter you among the peoples

"I will cause you to live among the people of other nations". Yahweh speaks of causing the Israelite people to live in other nations as if he scattered them like someone would scatter seeds.