Will be restrained from them, which they have imagined to do. Genesis 11:6

Once the couple is united, the fusion produces a spiritual force that will make it impossible for anything to restrain them from achieving whatever they imagined to do. When a couple is united, there is no force strong enough to stop them from achieving any of their desires. This means that all the couple's desires, including the fruit of the womb, good  health, prosperity and longevity will become fulfilled in their lives if they are united. Because the devil cannot restrain any couple from achieving their hearts' desires unless they are disunited, his focus is to cause disunity among couples. This divided-and-rule tactic of the devil is the major weapon he uses against marriages.