Originally of sound — the low murmuring of a dove or the rumbling of a lion over its prey — hagah came to mean the quiet, repetitive vocalization of someone absorbing a text or thought. Biblical meditation was fundamentally oral: you murmured the words until they soaked in, not a silent emptying but an active filling.
Psalm 1's foundational portrait of the blessed person is someone who hagahs God's law day and night. This is not speed-reading Scripture but rumination — like a cow chewing cud, returning to the same passage again and again until it becomes part of you. Joshua 1:8 ties this directly to success: 'meditate on it day and night... then you will have good success.'