# Father, forgive them

The word "them" refers to those who were crucifying Jesus.

# Father

This is an important title for God. 

# for they do not know what they are doing

The Roman soldiers did not know that they were crucifying the Son of God. Alternate translation: "because they do not understand what they are doing." 

# they cast lots

The soldiers participated in a type of gambling. Alternate translation: "they gambled"

# cast lots, dividing up his garments

"cast lots to decide who among the soldiers would take home each piece of Jesus's clothing"