[Jhn 2:16, 19 NKJV]
16 And He said to those who sold doves, "Take these things away! Do not make My Father's house a house of merchandise!" ...
19 Jesus answered and said to them, "Destroy this temple, and in three days I will raise it up."
According to verse 16, the Father's house is the physical temple in Jerusalem. However, according to verse 19, the Father's house is now the spiritual temple of Jesus' body. Both are true statement because the physical temple in Jerusalem is an Old Testament type of the spiritual temple: the body of Jesus.
Initially the temple is only the individual body of Jesus, but through His death and resurrection on the third day, Jesus enlarges the Father's house to make room for all His believers. Now all His believers are part of the "resurrected" temple (1 Corinthians 3:16) to be the Father's house, the dwelling place of God in spirit (Ephesians 2:21-22) on the earth.
To accomplish this, Jesus has to go to the Father (John 14:2, 12). But where is the Father? Most Christians will assume that the Father is in heaven. But Jesus Himself said in verse 10 that the Father is actually in Him (John 14:10). This is because according to John 2:19 and 21 the Father has "moved out" from the Old Testament temple into the New Testament temple: Jesus. Jesus is now the New Testament Father's house. He is the moving-walking-living temple.
So between Jesus and the Father there is no separation. Jesus and the Father are indwelling one another. They are one! However, between His disciples and the Father, there is still a great spiritual distance.
Jesus Himself becomes the unique way to bridge this great gap by His resurrection that allows Him to give His divine life to His believers (John 14:6, 11:25). This connects John 2:19 with John 14:2 where He says that He will raise up the Father's house in three days.
So His going to the Father involves His going to shed His blood on the cross to remove the barriers righteously and reconcile the spiritual gap between God and man through His resurrection. Now by believing into Jesus, man can have access in one Spirit to, not just to God, but to the Father. This means His believers are no longer merely His creatures but His family, His household, His dwelling place on the earth: the enlargement of the Father's house.
[Eph 2:13, 16, 18, 19 NKJV]
13 But now in Christ Jesus you who once were far off have been brought near by the blood of Christ. ...
16 and that He might reconcile them both to God in one body through the cross, thereby putting to death the enmity. ...
18 For through Him we both have access by one Spirit to the Father.
19 Now, therefore, you are no longer strangers and foreigners, but fellow citizens with the saints and members of the household of God,