As to the word basileia, it denotes sovereignty, which requires the actual presence of a sovereign, or king.  There can be no kingdom apart from a king.  We all know of countries which were once "kingdoms" but are now "republics", for the simple but sufficient reason that they have no "king", but are governed by the "public", which is sovereign.

The countries remain the same, have the same peoples, the same cities, the same mountains and rivers, but they are no longer kingdoms. The common practice of taking the Kingdom as meaning the Church (See Ap. 113), has been the source of incalculable misunderstanding; and not "trying the things that differ" (Phil. 1:10, see note there) has led to great confusion in the interpretation of the whole of the New Testament.

The following definitions may help towards a clearer view of many important passages :--

1. "The Kingdom of Heaven".   The word "heaven" is generally in this connection in the plural, "of (or from) the heavens".  For the difference between the use of the singular and plural of this word, see the  notes on Matt. 6:9, 10.  This expression is used only in the Gospel of Matthew, as being specially in harmony with the purpose of that Gospel.  See notes on pp. 1304-5, and Ap. 114.

   It is the dispensational term; and is used sometimes of the Messiah's Kingdom on earth, and sometimes of the heavenly sovereignty over the earth.  It is not from or out of (Gr. ek, Ap. 104. vii) "this world" (Gr. kosmos Ap. 129. 1).  This sovereignty comes from heaven, because the King is to come from thence (John 18:36).  It was to this end He was born, and this was the first subject of His ministry (see Ap. 119).  That Kingdom (Matt. 4:17, &c.) was rejected, as was also the further proclamation of it in Acts 3:19-26 (according to the prophetic parable of Matt. 22:2-7).  Thenceforth the earthly realization of this Kingdom was postponed, and is now in abeyance until the King shall be sent from heaven (Acts 3:20).  The "secrets" of this Kingdom (Matt. 13:11) pertained to the postponement of its earthly realization, on account of its being rejected.
   
   

2. "The Kingdom of God" is the sovereignty of God, which is moral and universal.  It existed from the beginning, and will know no end.  It is over all, and embraces all.  See Ap. 114.
   
   
3. "The Kingdom of the Father".  (Matt. 13:43) is not universal, but has regard to relationship, and  "a heavenly calling" (Heb. 3:1), and to the heavenly sphere of the Kingdom, in its relation to the earthly.  It is sovereignty exercised toward obedient sons, when the Son of man shall have gathered out of His Kingdom "all things that offend" (Matt. 13:41).  Cp. Dan. 7:25-27.  Matt. 25:31-46.  Luke 20:34-36.  The way of entrance into this may be seen in John 3:3.  It is going on now concurrently with No. 5.
   
   
4. "The Kingdom of the Son of man".  (Matt. 16:28).  This aspect of "the Kingdom of heaven" has regard to Israel on earth (cp. Dan. 7:13, 14, 18, 21, 22), as distinct from the "sons" who, as partakers of "a heavenly calling" (Heb. 3:1), will possess the heavenly sphere as sons of the resurrection (Luke 20:34-36.  Cp. 1Cor. 15:23.  Rev. 20:4-6).  These two spheres are distinct, though they ar a8c e one.  No. 3 concerns "the saints of the most high [places]" (Dan. 7:18, 24).  No. 4 concerns "the people of the saints of the most high".  These have their portion in "the Kingdom under the whole heaven", which has regard to earthly sovereignty, in which "all dominions shall serve and obey Him" (Dan. 7:27).

   These two would have had their realization even then, had Israel repented at the summons of the Lord, and of "them that heard Him" in Acts 3:19-26.  In that case the later revelation of the "Mystery" (or the great secret) which with its exanastasis and its "heavenward Call" (Phil. 3:11, 14), was hidden in God, would have remained in the keeping of the Father's Divine sovereignty.
   
   

5. "The Kingdom of His dear Son".  Gr. the Kingdom of the Son of His love, or of His beloved Son (Col. 1:13), has regard to quite another sphere, above all heavens, and refers to the sovereignty of God's beloved Son as made the "Head over all things to His ekklesia, which is His body, the fulness of Him that filleth all in all" (Eph. 1:10, 20-23).  See also Eph. 5:5.

   This sovereignty had been "kept secret" (Rom. 16:25), "hid in God (Eph. 3:9), "hid from ages and from generations" (Col. 1:25); but after the Kingdom (No. 4) proclaimed by the Lord and by "them that heard Him" (Heb. 2:4) had been postponed, it was revealed and "made known" (Eph. 3) for the "obedience of faith" (Rom. 16:26).  The subjects of this Divine sovereignty, on their believing this subsequent revelation, are "sealed" (or designated) for their inheritance, which is to be enjoyed with Christ (Eph. 1:13).

   This relates to the position of those who come under that sovereignty.
   
   

6. "The Everlasting Kingdom of our Lord and Saviour Jesus Christ".  (2Pet. 1:11).  This has regard to No. 5, but was then future (not having been revealed when Peter wrote); but it relates to the outward display of His sovereignty in millennial glory; while No. 5 relates to the inward position and experimental enjoyment of it in present grace.
   
   
7. "The Kingdom of our Lord and of His Christ" (or Messiah).  (Rev. 11:15).  This has regard to the end of the present time of abeyance of Nos. 3 and 4, and the millennial manifestation of both by Divine power, and in glory.  See also Rev. 12:10.

At the end of the  thousand years, No. 1, and perhaps others of them will cease, and be absorbed in the Kingdom of God (No. 2).