Hint.
What squeaks and squawks when thirsty,
But grows black if drinks extreme,
Bears the weight of Heaven’s gate,
And comes in twos and threes?
What holds castles together,
But with a pin can fall apart,
Is at the end of many days,
And is also at the start?
What was here before time,
And will be here for much, much more,
Swings the knuckles and never buckles,
And sees saucy secrets galore?
What is made from fire and earth,
Is leaves upon the lumber,
Fast in anger and slow in silence,
And closed during slumber?