Even them will I bring to my holy mountain, and make them joyful in my house of prayer: their burnt offerings and their sacrifices shall be accepted upon mine altar; for mine house shall be called an house of prayer for all people.
Even them - (Ephesians 2:11-13.)
Will I bring to my holy mountain - Jerusalem, the seat of the Lord's throne in His coming Kingdom (Isaiah 2:2; Jeremiah 3:17).
Make them joyful - (Romans 5:11.)
Their burnt offerings and their sacrifices - spiritual, of which the literal were types (Romans 12:1; Hebrews 13:15; 1 Peter 2:5).
(Shall be) accepted - (Ephesians 1:6.)
Upon mine altar (Hebrews 13:10) - spiritually, the cress of Christ, which sanctifies our sacrifices of prayer and praise.
An house of prayer for all people - or rather, peoples. No longer restricted to one favoured people (Malachi 1:11; John 4:21; John 4:23; 1 Timothy 2:8). To be fully realized at the second coming (Isaiah 2:2-4). No longer literal, but spiritual sacrifice, namely, "prayer," shall be offered (Psalms 141:2; Psalms 51:17; Matthew 21:13).