Adam Clarke's Bible Commentary Verse 3. And Abram fell on his face] The eastern method of prostration was thus: the person first went down on his knees, and then lowered his head to his knees, and touched the earth with his forehead. A very painful posture, but significative of great humiliation and reverence.
Matthew Henry Commentary
Verses 1-6 - The covenant was to be accomplished in due time. The promised Seed wa Christ, and Christians in him. And all who are of faith are blesse with faithful Abram, being partakers of the same covenant blessings. I token of this covenant his name was changed from Abram, "a hig father," to Abraham, "the father of a multitude." All that the Christian world enjoys, it is indebted for to Abraham and his Seed.
Original Hebrew ויפל5307 אברם87 על5921 פניו6440 וידבר1696 אתו854 אלהים430 לאמר׃559