Abraham received his promise after he patiently waited on God. Abraham was persuaded that he who promised was able to fulfill it.
18 Who against hope believed in hope, that he might become the father of many nations, according to that which was spoken, So shall thy seed be. 19 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 Sara’s womb: 20 He staggered not at the promise of God through unbelief; but was strong in faith, giving glory to God; 21 And being fully persuaded that, what he had promised, he was able also to perform.
After waiting patiently, Abraham received what was promised. (Hebrews 6:15) Abraham was tested for a very long time, but he was richly rewarded. The Lord tested him by delaying the fulfillment of His promise. Satan tested him through temptation, and people tested him through their jealousy, distrust, and opposition to him. Sarah tested him through her worrisome temperament. Yet he patiently endured, not questioning God’s truthfulness and power or doubting God’s faithfulness and love. Instead, Abraham submitted to God’s divine sovereignty and infinite wisdom. And he was silent through many delays, willing to wait for the Lord’s timing. Having patiently endured, he then obtained the fulfillment of the promise.