1. To weigh in the mind; to consider and compare the circumstances or consequences of an event, or the importance of the reasons for or against a decision.
Mary kept all these things, and pondered them in her heart. Luke 2.
2. To view with deliberation; to examine.
Ponder the path of thy feet. Prov 4.
The Lord pondereth the hearts. Prov 21.
To ponder on, is sometimes used, but is not be to countenanced.