"In the gospel of Matthew besides the mention of His universal assembly, the Lord gives us His thoughts concerning a local assembly, as composed though it may be of only 'two or three' persons (18: 15-20). Though suffering still from His rejection, expressed in chapter 11, the Lord was already looking forward to the dawn of that time when He would make known to His brethren as their present portion the relationship with the Father which He came to reveal; when also these same redeemed ones would be gathered together in His name on earth. The Lord's heart must have been indeed, if we may so say, blessedly preoccupied with that coming time, when teaching the lesson of grace towards little children (Matt. 18:1-14), and of the exercise of this same grace amongst 'brethren' (vv 15-16), for He seizes the opportunity for speaking of the assembly in the following verses—no longer of the Church as a whole, but of the local assembly, though it might be found in the smallest possible number. Thus we have from the Lord's own mouth the words which reveal to us the character and duty of an assembly of God upon which the Lord confers His authority to act on His behalf and in His name, so that the acts of this assembly are bound in heaven. This passage therefore is of the last importance. It is not repeated in the epistles of Paul, which contain, however, its development and application.
"It is plain the Lord had before Him in Matt. 18 a local assembly which would, and should today, comprise all saints living in the locality. The two brethren, one of whom had trespassed against the other, both belonged to the assembly; and this it is which gives so serious an importance to the action of the one whose duty it was to gain his brother. The one or two more whom he was to take with him as a last resort before communicating the matter to the assembly, also doubtless formed part of it. The same may be said of the 'two of you' mentioned in verse 19.
"The value which the Lord attaches to such an assembly is brought to us by the fact that if the brother who had sinned against the other refused to hear the 'Church' all was over. There was no fourth effort to be made, since he had despised the assembly in which the Lord was present, and His name to which they are gathered.
"An assembly of God is shown to be such by the Lord's table spread in its midst. A gathering of Christians which had not the Lord's Table would not constitute an 'assembly.' But the Lord's authority for administration amongst those gathered around the table is found in connection with the ordinance which calls Him to mind. Further, the Lord's Table spread in different assemblies of God is that which establishes and proves their joint responsibility, for they profess subjection to the authority of the same Lord. Finally, without the Lord's Table there would be no discipline; for there would be nothing to prove that they hold fast to His name to which they are professedly gathered." (F. P. B. French.)