Gregory of Nyssa: Pillar and Ground of Truth is Timothy

Whenever the prophet looks to the tabernacle above, he sees the heavenly realities through these symbols. But if one should look at the tabernacle below (since in many places the Church also is called Christ by Paul), it would be well to regard the names "apostles, teachers, and prophets" as referring to those servants of the divine mystery whom Scripture also calls pillars of the Church. For it is not only Peter and John and James who are pillars of the Church, nor was only John the Baptist a burning light, but all those who themselves support the church and become lights through their own works are called "pillars" and "lights." You are the light of the world, says the Lord to the Apostles. And again the divine Apostle bids others to be pillars, saying Be steadfast and unmovable. And he made Timothy into an excellent pillar, when he made him (as he says in his own words) a pillar and ground of truth.

- Gregory of Nyssa (around A.D. 335 to around A.D. 395), The Life of Moses, Section 184, p. 101 (1978), Malherbe et al. editors