The word "secret" describes the things that people do secretly. Things that are shameful should cause people who do them to feel ashamed. Alternate translation: "the things that people do secretly because they cause shame" (See: [[rc://en/ta/man/translate/figs-hendiadys]])
"Word of God" here is a metonym for the message from God. This phrase uses two negative thoughts to express a positive thought. Alternate translation: "we do not mishandle God's message" or "we use the word of God correctly" (See: [[rc://en/ta/man/translate/figs-doublenegatives]] and [[rc://en/ta/man/translate/figs-metonymy]])
This refers to God's presence. God's understanding and approval of Paul's truthfulness is referred to as God being able to see them. Alternate translation: "before God" or "with God as witness" (See: [[rc://en/ta/man/translate/figs-metaphor]])