OUTLINE:

"Forensic" at Dictionary.com
pertaining to, connected with, or used in courts of law or public discussion and debate.

Big Picture
The NT letters were written years later to the very same churches the apostles founded and built in the book of Acts!! (i.e. - Paul's missionary trips took him to Galatia, Thessalonica, Ephesus, Corinth, Rome, etc... and he later wrote to them, often defending the Gospel from attacks he heard about)  

Heb 4:13
And there is no creature hidden from His sight, but all things are open and laid bare to the eyes of Him with whom we have to do.

Sharing the Gospel
"You say you have no sin?? God knows the heart. In fact, Jesus said if you even just THINK something, you've DONE IT in God's eyes. Think maybe you need to repent towards God, my friend?"

The Gospel Is Simple
It's just not "easy" for man because man holds on to a stubborn and unrepentant heart. Ro 2:4-5

His call to us opened our ears and even empowered us to call upon Him to be saved.

Man's call out to God to be saved is actually a response to the call of the Holy Spirit. It's the Lord who reaches out to save man. Ac 2:39,47

We Rejoice!
This is supernatural! God's reaching out to the spiritually deaf and convicting man's heart to a response that saves!

Our Lord is both Justice and Mercy. He is the Lion and the Lamb. We don't have a King who is weak in any way, "full of grace and truth". Jn 1:14

The Lord calls and saves, and shares His very own Righteousness with those who are humbly willing to drop their own righteousness. Lk 18:9-14

Mk 1:15b
"repent and believe the good news!"

Ac 26:17b-18 NIV
‘I am sending you to them to open their eyes and turn them from darkness to light, and from the power of Satan to God, so that they may receive forgiveness of sins and a place among those who are sanctified by faith in me.'

Ac 5:29 Truth In Context
This doesn't give us the right to act arrogantly in the face of authorities that are against Christ. On the contrary, it's speaking the truth in love, humbly saying "this is what I must do because God said so".

God gives His Holy Spirit to those who obey Him. Ac 5:32