Why should we question such a plain statement? And when it's likewise attested to in other places,
Ephesians 2:4-6 KJV
4) But God, who is rich in mercy, for his great love wherewith he loved us,
5) Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved
6) And hath raised us up together, and made us sit together in heavenly places in Christ Jesus:
Colossians 3:1-4 KJV
1) If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God.
2) Set your affection on things above, not on things on the earth.
3) For ye are dead, and your life is hid with Christ in God.
4) When Christ, who is our life, shall appear, then shall ye also appear with him in glory.
Much love!