There is such a thing in the commercial world as "the present worth" of a bill or promissory note; for if men are called upon to wait for their money, they must be paid for waiting. Now, in faith's world, there is such a thing as the _present_ worth of God's promise; and the scale by which that worth is regulated is the heart's experimental knowledge of God; for according to my estimate of God, will be my estimate of his promise; and moreover, the subdued and patient spirit finds its rich and full reward in waiting upon him for the accomplishment of all that he has promised. However, as to Sarah, the real amount of her word to Abraham is this, "The Lord has failed me; it may be, my Egyptian maid will prove a resource for me." Any thing but God for a heart under the influence of unbelief. It is often truly marvellous to observe the trifles to which we will betake ourselves when once we have lost the sense of God's nearness, his infallible faithfulness, and unfailing sufficiency. We lose that calm and well-balanced condition of soul so essential to the proper testimony of the man of faith; and, just like other people, betake ourselves to any or every expedient, in order to reach the wished-for end, and call that "a laudable use of means." But it is a bitter thing to take ourselves out of the place of absolute dependence upon God. The consequences must be disastrous. Had Sarah said, "Nature has failed me, but God is my resource," how different it would have been! This would have been her proper ground; for nature really had failed her. But then it was nature in one shape, and therefore she wished to try nature in another. She had not learnt to look away from nature in every shape. In the judgment of God and of faith, nature in Hagar was no better than nature in Sarah. Nature, whether young or old, is alike to God; and, therefore, alike to faith; but, ah! we are only in the power of this truth when we are experimentally finding our living centre in God himself. When the eye is taken off that glorious Being, we are ready for the meanest device of unbelief. It is only when we are consciously leaning on the only true, the only wise, the living God, that we are enabled to look away from every creature stream. It is not that we shall despise God's instrumentality. By no means. To do so would be recklessness and not faith. Faith values the instrument, not because of itself, but because of him who uses it. Unbelief looks only at the instrument, and judges of the success of a matter by the apparent efficiency thereof, instead of by the sufficiency of him who, in grace, uses it. Like Saul, who, when he looked at David, and then looked at the Philistine, said, "Thou art not able to go against this Philistine to fight with him; for thou art but a youth." Yet the question in David's heart was, not as to whether he was able, but whether Jehovah was able.