Murray rightly believed that all Christians were filled with the Spirit at their regeneration — right at the very time when God the Holy Ghost implanted them with saving faith. That regeneration, and the resultant indwelling of the Spirit, is unlosable — even though the joy of [our] experiencing that indwelling is forfeited whenever unchecked sin recurs. Indeed, that joy in the Spirit can only be restored upon a fresh act of repentance. Ps. 51:1,10,12; Lam. 5:21f; Rev. 2:1-7 & 3:14-22.
Precisely at this very point, it is indeed helpful to indicate the relationship between the three [then contemporary] Presbyterians — Benjamin Warfield, Asa Mahan, and Andrew Murray.