Hebrew hagah — "to murmur, mutter, growl, ponder" — and siach — "to muse, to talk to oneself." The Hebrew picture of meditation is that of a lion growling over its kill (the same verb hagah, Isaiah 31:4) or a cow chewing its cud — working the same substance over and over, extracting every particle of nourishment. It is emphatically not emptying the mind (Eastern meditation) but filling the mind with God's Word and turning it over and over.
Biblical meditation is not zen, mantra, or mindfulness. It is the active, verbal, persistent working-over of Scripture in the mind until it becomes the bloodstream of the soul. "This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night" (Joshua 1:8). "Blessed is the man... whose delight is in the law of the LORD, and on his law he meditates day and night" (Psalm 1:1-2). "I will meditate on your precepts and fix my eyes on your ways" (Psalm 119:15). The practice: take one verse (or paragraph or psalm), read it slowly, say it aloud, consider what each word means, ask what it demands, pray it back, and return to it throughout the day. Memorization greatly deepens meditation because it makes the text portable. Where modern meditation seeks silence within, biblical meditation seeks Scripture within — and from that, a silence that is also a hearing. The saint who has meditated on a psalm all day is harder to deceive, harder to tempt, harder to shake, and closer to God than the one who merely read the psalm and closed the Bible.