"And this is life eternal, that they might know Thee the only true God, and Jesus Christ whom Thou hast sent" (John 17:3).
The essence of truth and reality is God, and the essence of God is that He is Father, Son, and Holy Spirit dwelling in perfect oneness.
"The LORD our GOD is one LORD" (Deuteronomy 6:4).
The fact of God calls us to the great intellectual pursuit of our existence. The character of God calls us to the great moral pursuit of our existence. The nature of God calls us to the awed worship of our existence. The promise of God calls us to the faith and trust of our existence. The love of God calls us to the devotion of our existence, and the trinity of God calls us to the relationship of our existence.
The last point has been the subject of these considerations. God Himself exists, and has always existed, within the context of relationship. He has forever been as He is - "I am the Lord; I change not" - and thus He has forever existed as Father, Son, and Holy Spirit (Malachi 3:6). It does not injure Biblical revelation to say that God is Himself a family. He is one, and yet there are three distinct personages in the Godhead. The three relate to one another in the perfection of love, and all other relationships in the universe are meant to mirror or image the glory of the Divine union. For the trusting sons and daughters of God in the Lord Jesus Christ, eternity will involve both the witnessing of this beauty, and also active participation because "the love of God is shed abroad in our hearts by the Holy Spirit which is given unto us" (Romans 5:5). The Lord Jesus asked His Father "that the love wherewith Thou hast loved Me may be in them," and His prayer was answered (John 17:26).
Certainly our understanding and experience of this hope of glory is limited in our present existence. But just as certainly, mere glimpses of the glory are enough to fill our heart to overflowing. God's grace in Christ has not only forgiven us and promised us an eternity in Heaven. It has also made us into the very temple of the Triune, and the holy scene where the Father, the Son, and the Holy Spirit are known in expressions that would forever remain unknown without us. Indeed, the grace and mercy purposed by the Father, purchased by the Son, and provided by the Holy Spirit would have been hidden qualities in the Divine heart apart from the torrents now and forever showered forth upon believers in the Lord Jesus. The Apostle Paul wrote to the Ephesians of this indescribable wonder, and we close our thoughts about the Father and the Son with Paul's promise of a forever that will not suffice in fully revealing the glory of God...
"But God, who is rich in mercy, for His great love wherewith He loved us, even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;) and hath raised us up together, and made us sit together in heavenly places in Christ Jesus: that in the ages to come He might show the exceeding riches of His grace in His kindness toward us through Christ Jesus."