If Heaven is eternal and timeless, how is it possible for there to be a time where one can leave Heaven, like the Son did?
Phillippians 2:5
Have this mind among yourselves, which is yours in Christ Jesus, 6 who, though he was in the form of God, did not count equality with God a thing to be grasped,7 but emptied himself, taking the form of a servant,[a] being born in the likeness of men. 8 And being found in human form he humbled himself and became obedient unto death, even death on a cross. 9 Therefore God has highly exalted him and bestowed on him the name which is above every name, 10 that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
The Word of God became flesh and made His dwelling among us, being born of a (Virgin) Woman, for as the blessed Virgin Mary proclaimed from her fiat, “for nothing is impossible for God”.
What follows your “impossible” question, deals with the prophecy from Simeon in the temple; “he will be a sign of contradiction”. This sign of contradiction deals on many fronts, especially the subject you raise here between things eternal and things temporal.
There are two terms which apply here, and can answer your “impossibility”?
- Deals with God’s Presence. God can make His Presence known both eternally and in space and time, especially when it comes to God’s Word and God’s Spirit. Thus, God’s Presence is made known in the incarnation of Jesus Christ. Angels can also make there presence known to us, although the Seraphim Choir of angels do not come down to us, Partly because they are eternally presence in God’s eternal presence aflamed.
- Deals with Divine procession. In the Trinity, The Father never proceeds, when the Son eternally proceed’s from the Father and the Holy Spirit proceeds from the Father and the Son to make divine revelation known to all of creation and in space and time.
Peace be with you