'That the Christian's strength is in the Lord.’ Now we shall give some demonstrations [or reasons].
[Why the saint's strength is laid up in God.]
Reason First. The first reason may be taken from the nature of the saints and their grace. Both are creatures, they and their grace also. Now it is in the very nature of the creature to depend on God its Maker,’ both for being and operation. Can you conceive and accident to be out of its subject, whiteness out of the wall, or some other subject? It is impossible that the creature should be, or act without strength from God. This to be, act in and of himself, is so incommunicable a property of the Deity, that he cannot impart it to his creature. God is, and there is none besides him. When God made the world, it is said indeed he ended his work, that is, of creation: he made no new species and kinds of creatures more; but to this day he hath not ended his work of providence: 'My Father worketh hitherto,’ saith Christ, John 5:17, that is, in preserving and empowering what he hath made with strength to be and act, that therefore he is said to hold our souls in life. Works of art, which man makes, when finished, may stand some time without the workman's help, as the house, when the carpenter that made it is dead; but God's works, both of nature and grace, are never off his hand, and therefore as the Father is said to work hitherto for the preservation of the works of nature, so the Son, to whom is committed the work of redemption, he tells us, worketh also. Neither ended he his work when he rose again, any otherwise than his Father did in the work of creation. God made an end of making, so Christ made an end of purchasing mercy, grace, and glory for believers, by once dying; and as God rested at the end of creation, so he, when he had wrought eternal redemption, and 'by himself purged our sins, sat down on the right hand of the Majesty on high,’ Heb. 1:3. But he ceaseth not to work by his intercession with God for us, and by his Spirit in us for God, whereby he upholds his saints, their graces, and comforts his life, without which they would run to ruin. Thus we see as grace is a creature, the Christian depends on God for his strength. But further,
Reason Second. The Christian's grace is not only a creature, but a weak creature, conflicting with enemies stronger than itself, and therefore cannot keep the field without an auxiliary strength from heaven. The weakest goes to the wall, if no succour comes in. Grace in this life is but weak, like a king in the cradle, which gives advantage to Satan to carry on his plots more strongly to the disturbance of this young king's reign in the soul, yea, he would soon make an end of the war in the ruin of the believer's grace, did not Heaven take the Christian into protection. It is true indeed, grace, wherever it is, hath a principle in itself that makes it desire and endeavour to preserve itself according to its strength, but being overpowered must perish, except assisted by God, as fire in green wood, which deads and damps the part kindled, will in time go out, except blown up, or more fire put to that little; so will grace in the heart. God brings his grace into the heart by conquest.
Now, as in a conquered city, though some yield and become true subjects to the conqueror, yet others plot how they may shake off this yoke; and therefore it requires the same power to keep, as was to win it at first. The Christian hath an unregenerate part, that is discounted at this new change in the heart, and disdains as much to come under the sweet government of Christ's sceptre, as the Sodomites that Lot should judge them. What, this fellow, a stranger, control us! And Satan heads this mutinous rout against the Christian, so that if God should not continually reinforce this new planted colony in the heart, the very natives (I mean corruptions) that are left, would come out of their dens and holes where they lie lurking, and eat up the little grace the holiest on earth hath; it would be as bread to these devourers.