John 7:33 (NIV)
I am with you for only a short time.
Although Christ is with us for all eternity, He occasionally hides His Presence from us. At times there are dark clouds that surround the Lord and hide His Presence from us. That doesn't mean that He isn't with us, it only means that we can't consciously sense His Presence. The Lord Himself faced such moments on the cross when a Holy God could not look upon sin. Sometimes the Lord is hid from us because of unconfessed sin, while at other times due to our self-righteousness. Only a penitent and humble soul will always see the Lord.