A.T. Robertson Commentary Luke 2:19

"But Mary kept all these sayings, pondering them in her heart." — Luke 2:19 (ASV)

Kept (συνετηρε). Imperfect active. She kept on keeping together (συν-) all these things. They were meat and drink to her. She was not astonished, but filled with holy awe. The verb occurs from Aristotle on. She could not forget. But did not Mary keep also a Baby Book? And may not Luke have seen it?

Pondering (συνβαλλουσα). An old Greek word. Placing together for comparison. Mary would go over each detail in the words of Gabriel and of the shepherds and compare the sayings with the facts so far developed and brood over it all with a mother's high hopes and joy.