Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
There are two things connected with the presence of the multitude, Mat 5:1. First, the time required that the Lord should give a true idea of the character of His kingdom, since already He drew the multitude after Him. His power making itself felt, it was important to make His character known. On the other hand, this multitude who were following Jesus were a snare to His disciples; and He makes them understand what an entire contrast there was between the effect which this multitude might have upon them, and the right spirit which ought to govern them. Thus, full Himself of what was really good, He immediately brings forward that which filled His own heart. This was the true character of the remnant, who in the main resembled Christ in it. It is often thus in the Psalms.
The salt of the earth is a different thing from the light of the world. The earth, it appears to me, expresses that which already professed to have received light from God that which was in relationship with Him by virtue of the light having assumed a definite shape before Him. The disciples of Christ were the preservative principle in the earth. They were the light of the world, which did not possess that light. This was their position, whether they would or no. It was the purpose of God that they should be the light of the world. A candle is not lighted in order to be hidden.
All this supposes the case of the possibility of the kingdom being established in the world, but the opposition of the greater part of men to its establishment. It is not a question of the sinner's redemption, but of the realisation of the character proper to a place in the kingdom of God; that which the sinner ought to seek while he is in the way with his adversary, lest he should be delivered to the judge which indeed has happened to the Jews.
At the same time the disciples are brought into relationship with the Father individually the second great principle of the discourse, the consequence of the Son being there and a yet more excellent thing is set before them than their position of testimony for the kingdom. They were to act in grace, even as their Father acted, and their prayer should be for an order of things in which all would correspond morally to the character and the will of their Father. "Hallowed be thy name, thy kingdom come," [See Note #22] is, that all should answer to the character of the Father, that all should be the effect of His power. "Thy will be done on earth as it is in heaven" is perfect obedience. Universal subjection to God in heaven and on earth will be, to a certain point, accomplished by the intervention of Christ in the millennium, and absolutely so when God shall be all in all. Meanwhile the prayer expresses daily dependence, the need of pardon, the need of being kept from the power of the enemy, the desire of not being sifted by him, as a dispensation of God, like Job or Peter, and of being preserved from evil.
This prayer also is adapted to the position of the remnant; it passes over the dispensation of the Spirit, and even that which is proper to the millennium as an earthly kingdom, in order to express the right desires, and speak of the condition and the dangers of the remnant until the Father's kingdom should come. Many of these principles are always true, for we are in the kingdom, and in spirit we ought to manifest its features; but the special and literal application is that which I have given. They are brought into relationship with the Father in the realisation of His character, which was to be displayed in them by virtue of this relationship, causing them to desire the establishment of His kingdom, to overcome the difficulties of an opposing world, to keep themselves from the snares of the enemy, and to do the Father's will. It was Jesus who could impart this to them. He thus passes from the law, [See Note #23] recognised as coming from God, to its fulfilment, when it shall be as it were absorbed in the will of Him who gave it, or accomplished in its purposes by Him who alone could do so in any sense whatever.
That is, the Father's. Compare Mat 13:43.
The law is the perfect rule for a child of Adam, the rule or measure of what he ought to be, but not of the manifestation of God in grace as Christ was, who in this is our pattern a just call to love God and walk in the fulfilment of duty in relationship, but not an imitating of God, walking in love, as Christ has loved us and given Himself for us.