In Genesis 17:1 we are told, "And when Abram was ninety years old and nine, the LORD appeared to Abram, and said unto him, I am the Almighty God; walk before me, and be thou perfect."
Thirteen years had gone by since Abraham had hearkened unto Sarah, and during this time there was no mention of God's appearing to Abraham.
In the Scriptures these 13 years are passed over as a period of spiritual barrenness. For Abraham it was what is known spiritually as a time of wood, hay and stubble.
But why all of this waiting? God had promised Abraham a son, and by this time only Ishmael had been born into his home--by a means that was not pleasing to the Lord. The reason for God's delay was so God could bring Abraham to the end of himself.
Later it was said of Abraham, "And being not weak in faith, he considered not his own body now dead, when he was about an hundred years old, neither yet the deadness of Sarah's womb" (Rom. 4:19).
Before divine power is put forth, man must learn his own impotency. Not until Abraham's body was as good as dead would God fulfill His word.
Man's extremity is God's opportunity. Though to Abraham this seemed like a long delay, God was right on time. God has a perfect time for everything.
"As for God, his way is perfect" (Ps. 18:30).