Hebrews 4:16

The word for boldness is the interesting one. In classical Greek it belonged to the assembly — the right of a citizen to speak freely in public, to say the unpopular thing without penalty. It is a political word about standing, not an emotional word about confidence.

So the instruction is not feel brave. It is use the access you have been given.

And it is a throne. The writer does not soften that. Thrones are where verdicts are issued, and a throne is not somewhere you approach casually. What he changes is the adjective: the throne of grace. The authority is undiminished; the disposition of the one seated on it has been made known.

The therefore points backwards, and the reason it points to is the previous two verses. We have a high priest who has been tempted in every way as we are. The boldness is not based on your record being adequate. It is based on the sympathy of the person who takes your case, who is not being told about the difficulty second-hand.

Then two things are named, and they are not the same. Mercy — for what has already gone wrong, the past dealt with. Grace for help in time of need — for what is coming, help arriving on schedule. One looks back, one looks forward. The verse assumes you will require both, and does not treat needing them as a failure.