3) We would lose our power as witnesses to the truth of the assembly.

A third reason we need to walk in separation from denominational churches is that if we join ourselves to them we will lose our power as witnesses to the truth of the assembly. In the case of the prophet who returned to Bethel to eat bread with the old prophet, when he disobeyed the Word of the Lord and ate in that place, a lion killed him and that was the end of his story as a witness for the Lord.

The Lord said to Jeremiah: “If you return, then I will bring you back, and you will stand before me; and if you separate the precious from the vile, you will be as my mouth; let them turn to you, but do not you turn to them” (Jer. 15:19). The point we will see here is that, if Jeremiah remained separated from the corruption that was in Judah, he would continue to be used as the “mouth” of the Lord. If he returned and joined himself to the people, he would lose his power as a testimony. In the same way, if we remain in the ecclesiastical position in which we are because we have separated, we can and will be used to bear a testimony to the truth amid the confusion and, in a certain sense, to be the “mouth” of the Lord. We will be a “vessel for honor, sanctified and fit for the Master's use, and prepared for every good work” (2 Tim. 2:21). Those who remain in the confusion of denominational systems can be used by the Lord for some works, but not for “every good work.” They cannot be used to teach the truth of the assembly and the order proper to it -- at least not with power, since such truth condemns the position in which they find themselves. And if we return to that from which we separated, we will lose our power to testify.