To be sacred and set apart.

My tabernacle also shall be with them: yea, I will be their God, and they shall be my people. And the heathen shall know that I the LORD do SANCTIFY Israel, when my sanctuary shall be in the midst of them for evermore. ( Ezekiel 37:27-28 )

Source: A King James Dictionary. (Used with permission. Copyright © Philip P. Kapusta)

Bibliography Information

"Entry for 'Sanctify'". A King James Dictionary.