Then I don't know how much clearer it can be than to say "He will appear a second time" as the second coming unless you're arguing He didn't come the first time. This is a direct play off of the first appearance/coming. He literally gave His word to those who were eagerly waiting for Him, as He did to the apostles in Matthew 16 and 24 and as He did to the churches in Revelation when He told them to "hold fast to what you have until I come"
Hebrews 9:
25Nor was it to offer himself repeatedly, as the high priest enters the holy places every year with blood not his own,
26for then he would have had to suffer repeatedly since the foundation of the world. But as it is,
he has appeared once for all at the end of the ages to put away sin by the sacrifice of himself
. 27And just as it is appointed for man to die once, and after that comes judgment,
28so Christ, having been offered once to bear the sins of many,
will appear a second time, not to deal with sin but to save those who
are eagerly waiting for him.
As to "coming down physically": Since God is Spirit and no one has seen Him at any time, so He did not come down physically, rather He, like the angels can manifest as a man. God doesn't literally "come down" as He is everywhere, He is omnipresent. It's a figure of speech.
Psalm 139:
7Where can I go to escape Your Spirit?
Where can I flee from Your presence?
8If I ascend to the heavens, You are there;
if I make my bed in Sheol, You are there.
9If I rise on the wings of the dawn,
if I settle by the farthest sea,
10even there Your hand will guide me;
Your right hand will hold me fast.
11If I say, “Surely the darkness will hide me,
and the light become night around me”—
12even the darkness is not dark to You,
but the night shines like the day,
for darkness is as light to You.