Explanatory Notes on the Whole Bible, by John Wesley, [1754-65], at sacred-texts.com
gen 20:1And Abraham sojourned in Gerar - We are not told upon what occasion he removed, whether terrified by the destruction of Sodom, or, as some of the Jewish writers say, because he was grieved at Lot's incest with his daughters, and the reproach which the Canaanites cast upon him for his kinsman's sake. The king of Gerar sent and took her - To his house, in order to the taking of her to his bed.
gen 20:3But God came to Abimelech in a dream - It appears by this that God revealed himself by dreams, which evidenced themselves to be divine and supernatural, not only to his servants the prophets, but even to those that were out of the pale of the church; but then usually it was with some regard to God's own people.
gen 20:4Wilt thou slay also a righteous nation - Not such a nation as Sodom.
gen 20:6I withheld thee from sinning against me - It is God that restrains men from doing the ill they would do; it is not from him that there is sin, but it is from him that there is not more sin, either by his influence on mens minds checking their inclination to sin, or by his providence taking away the opportunity. It is a great mercy to be hindered from committing sin, which God must have the glory of whoever is the instrument.
gen 20:9Thou hast done deeds that ought not to be done - Equivocation and dissimulation, however they may be palliated, are very ill things, and by no means to be admitted in any case. He takes it as a very great injury to himself and his family, that Abraham had thus exposed them to sin, What have I offended thee? - If I had been thy worst enemy, thou couldst not have done me a worse turn, nor taken a more effectual course to be avenged on me. Note, We ought to reckon, that those do us the greatest dislikedness in the world, that any way tempt us or expose us to sin, though they may pretend friendship, and offer that which is grateful enough to the corrupt nature. He challenges him to assign any just cause he had to suspect them as a dangerous people for an honest man to live among.
gen 20:10What sawest thou that thou hast done this thing - What reason hadst thou to think, that if we had known her to be thy wife, thou wouldst have been exposed to any danger by it?
gen 20:11I thought surely the fear of God is not in this place, and they will slay me - There are many places and persons that have more of the fear of God in them than we think they have; perhaps they are not called by our name, they do not wear our badges, they do not tie themselves to that which we have an opinion of; and therefore we conclude they have not the fear of God in their hearts!
gen 20:13When God caused me to wander from my father's house - Then we settled this matter. It may be, that God denied Abraham and Sarah the blessing of children so long to punish them for this sinful compact they had made to deny one another: if they will not own their marriage, why should God own it? But we may suppose, that alter this reproof they agreed never to do so again, and then presently we read, Gen 21:1-2, that Sarah conceived.
gen 20:16Thy brother is to thee a covering of the eyes - Thou must look at no other, nor desire to be looked at by any other. Yoke - fellows must be to each other for a covering of the eyes. The marriage - covenant is a covenant with the eyes, like Job's, Job 31:1.