The psalmist then wondered who could go into the sanctuary of such a great God on Mt. Zion (cf. Psalm 23:6). Who could have the courage to do so? Right actions (clean hands) and right attitudes (a pure heart) are necessary if one hopes to attain admission to His presence. Idolatry and bearing false witness, perhaps representing all sins God-ward and Prayer of Manasseh -ward, disqualify any potential worshipper. [source][source][source]