Pentecost - I

In resurrection Jesus is declared to be Lord! As Lord he wants His land inhabited. In Acts 1:8, Jesus commissions His followers,
"But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth."

At Pentecost, the Spirit comes! In interpreting the event to those around, Peter quotes the prophet Joel (Acts 2:17ff. quoting Joel 2:28-32),
'In the last days, God says,
I will pour out my Spirit on all people.
Your sons and daughters will prophesy,
your young men will see visions,
your old men will dream dreams.
Even on my servants, both men and women,
I will pour out my Spirit in those days,
and they will prophesy.
I will show wonders in the heaven above
and signs on the earth below,
blood and fire and billows of smoke.
The sun will be turned to darkness
and the moon to blood
before the coming of the great and glorious day of the Lord.
And everyone who calls
on the name of the Lord will be saved.'

Peter clearly identifies the Pentecost event with the coming of the new age!

I believe two other passages help us to understand the nature of the Spirit in this new age.

Jeremiah 31:33-34
"This is the covenant I will make with the house of Israel
after that time," declares the LORD.
"I will put my law in their minds
and write it on their hearts.
I will be their God,
and they will be my people.
No longer will a man teach his neighbor,
or a man his brother, saying, 'Know the LORD,'
because they will all know me,
from the least of them to the greatest,"
declares the LORD.

Ephesians 2:19-22
"Consequently, you are no longer foreigners and aliens, but fellow citizens with God's people and members of God's household, built on the foundation of the apostles and prophets, with Christ Jesus himself as the chief cornerstone. In him the whole building is joined together and rises to become a holy temple in the Lord. And in him you too are being built together to become a dwelling in which God lives by his Spirit."

God is no longer dwelling within Temple/Jerusalem but in Jesus/Church and his dwelling is by the Holy Spirit. Jesus has been definitively declared Lord in resurrection, and his Lordship is being worked out by the agency of the Holy Spirit in the people of God, the Church.
(see also 1 Cor 3:5-17 and 6:19)