Matthew Henry Commentary Genesis 15:2-6

"And Abram said, O Lord Jehovah, what wilt thou give me, seeing I go childless, and he that shall be possessor of my house is Eliezer of Damascus? And Abram said, Behold, to me thou hast given no seed: and, lo, one born in my house is mine heir. And, behold, the word of Jehovah came unto him, saying, This man shall not be thine heir; But he that shall come forth out of thine own bowels shall be thine heir. And he brought him forth abroad, and said, Look now toward heaven, and number the stars, if thou be able to number them: and he said unto him, So shall thy seed be. And he believed in Jehovah; and he reckoned it to him for righteousness." — Genesis 15:2-6 (ASV)

Though we must never complain about God, we have permission to complain to Him and to state all our concerns. It brings ease to a burdened spirit to share its situation with a faithful and compassionate friend. Abram's complaint was that he had no child, that he was never likely to have one, and that the lack of a son was so great a trouble to him that it took away all his comfort.

If we suppose that Abram looked no further than outward comfort, this complaint was to be blamed. But if we suppose that Abram, in this, had reference to the promised Seed, his desire was very commendable. Until we have evidence of our share in Christ, we should not rest satisfied. What will all this benefit me, if I go Christless? If we continue persistent in prayer, yet pray with humble submission to the divine will, we will not seek in vain.

God gave Abram a specific promise of a son. Christians may believe in God regarding the common concerns of this life; but the faith by which they are justified always relates to the person and work of Christ. Abram believed in God as promising Christ; they believe in Him as having raised Him from the dead (Romans 4:24). Through faith in His blood, they obtain forgiveness of sins.