升堂入室
Up into the hall, not yet the inner room
由也升堂矣，未入于室也。
You has climbed into the hall, but has not yet entered the inner room.
论语 · 先进篇
· our translation
Confucius on Zilu: he has reached the hall but not the inner room. 升堂入室 later means advancing from the surface of a subject toward its depth.
孔子评子路：已经上了厅堂，还没进内室。后来「升堂入室」专指学问由浅入深——「堂」是进门之后的第一重。
堂堂
Presence you can feel
堂堂乎张也，难与并为仁矣。
How imposing Zizhang is — and yet it is hard to reach humaneness alongside him.
论语 · 子张篇
· our translation
Zengzi calls Zizhang 堂堂 — grand in bearing. A name takes the upright presence, not the difficulty of working with him.
曾子说子张「堂堂」：气象盛大，但与人同处不易。名字取「堂堂」，要的是端正有气象那一面。