I am the Lord, I do not change. (Malachi 3:6)
There is a great difference between the old and the new, but that difference is not in God. The new covenant makes no difference in God. The covenant that is brought to us through the mediation of the Lord Jesus does not bring a different God to us. The difference is not in Him; that is, His nature and His standard are always the same, unchangeable. Grace never brings God down to a lower level. Grace does not make any difference to the holiness of God, or to the righteousness of God. The difference in the two covenants is not that of a change in God. His position remains as it ever was, perfect in holiness, perfect in righteousness. The difference is, firstly, in the mediators, secondly, in the ground upon which those mediators stand....
Oh, the snare of the platform idea that so often constitutes the whole conception of ministry, as though other people are not ministers at all. It is just as much your privilege to behold Christ as any man's in this universe, and, that being so, it is just as much your calling to minister what you see in Christ to others. Beholding Him, we are changed into the same image from one degree of glory to another. This is the latter glory, the glory of the new covenant. Christ is the glory of the new covenant. The difference is not in God, it is the difference between the mediators, and the difference in the position which we occupy because of the Mediator; we are now in Christ, Who satisfies God. The Lord give us the ministry issuing from a continuous and ever-growing contemplation of His fullness in Christ.
By T. Austin-Sparks from: Spiritual Ministry - Chapter 3