The Gospel alone is the principle or foundation of all true holiness

But I must nevertheless, preach and proclaim this freeness of grace to fellow sinners, whether they will hear, or whether they will forbear. Firmly persuaded, that this is the true grace of God, and the only sort of grace that can suit their condition, and that can upon a right principle or foundation, either relieve their consciences, purify their hearts, comfort their souls or direct their conduct, under the influence of the blessed Spirit. Yea, and I must look upon the welcome reception of this grace, together with holy fruits thereof, to be the true and proper proof of genuine Christianity in heart and life. - Samuel Pike, Free Grace Indeed!, pg. 3