The enemies here were the Samaritans, the Jews don't associate with them for they are unclean.
2 Peter 1:2 Grace and peace be yours in abundance through the knowledge of God and of Jesus our Lord.
Zerubabbel was one of the leaders the exile in Babylon, he helped the people in rebuilding the temple, and he refuses the enemies by helping them.
2 John 1:10-11 If anyone comes to you and does not bring this teaching, do not take them into your house or welcome them. 11 Anyone who welcomes them shares in their wicked work.
Matthew 10:16 I am sending you out like sheep among wolves. Therefore be as shrewd as snakes and as innocent as doves.
The enemy will discourage you and make you afraid. Frustrate means will bother. Discouragement and Fear are the two greatest obstacle in your faith in God.
Romans 8:1 Therefore, there is now no condemnation for those who are in Christ Jesus,
We believers should expect the opposition.
Proverbs 4:16 For they cannot rest until they do evil;
they are robbed of sleep till they make someone stumble.
Micah 2:1 Woe to those who plan iniquity,
to those who plot evil on their beds!
At morning’s light they carry it out
because it is in their power to do it.
Jesus came to rebuilt the ruined temple of our lives.