Isaac seems not to have been much tried, but to have spent his days in quietness. Jacob and Esau were prayed for; their parents, after being long childless, obtained them by prayer. The fulfilment of God's promise is always sure, yet it is often slow.
The faith of believers is tried, their patience exercised, and mercies long waited for are more welcome when they come. Isaac and Rebekah kept in view the promise of all nations being blessed in their posterity, therefore were not only desirous of children, but anxious concerning every thing which seemed to mark their future character.
In all our doubts we should inquire of the Lord by prayer. In many of our conflicts with sin and temptation, we may adopt Rebekah's words, “If it be so, why am I thus?” If a child of God, why so careless or carnal?
If not a child of God, why so afraid of, or so burdened with sin?