The “He” of John 16:8 is the Holy Spirit according to the context (v 7). Jesus is speaking to His followers and telling them that He will not always be with them. He will one day go back to the Father but He will send another Comforter. The Comforter is the Holy Spirit and He will convince (“convict”) them of what is wrong as well as what is right. Why does the Holy Spirit have to convince us of what is right? If we think about it, it stands to reason that if we don’t truly understand what is wrong (our sin problem) apart from the Holy Spirit, then we can't understand what it means to be right apart from the Holy Spirit.
Every man does what is right in his own eyes (Proverbs 16:2) and thus is depending on his own righteousness for his sin problem. However, Jesus goes on in His instruction to His disciples to talk about His righteousness (v 10) and His judgment (v 11). He is not talking about our righteousness but His righteousness. Since it is His righteousness, it is what He has done and not what we have done. He doesn’t talk about who we are, but who He is. The only righteousness that God will accept is His righteousness; and the only way you can have His righteousness is to receive the righteousness that is in Jesus Christ. You and I need His righteousness because there has only been one man who could go to God on His own righteousness and stand equal with God and that is Jesus. You cannot come to God except through Jesus Christ; and you can only come to Jesus through the Holy Spirit.
Isn't it wonderful how the entire Godhead (Father, Son and Spirit) work together to accomplish our salvation? Heavenly Father, I thank you for sending your only begotten Son to die on the cross as the righteous Redeemer. I am convinced there is no hope for me outside of righteousness. Thank you for meeting a need I could not meet. Thank you for so freely giving me total forgiveness of sin that I may stand before you uncondemed. Help me to live today in that newness of life. In Jesus' name, Amen.