Romans 7:3

She shall therefore certainly be counted an adulteress, if, her husband being alive, she be for another man: but if her husband is dead, she is free from the law; so that she shall be no adulteress, though married to another husband.

Matthew 5:32

But I say unto you, Whosoever shall put away his wife, except on account of whoredom, causeth her to commit adultery: and whosoever shall marry her that is put away, committeth adultery.

Mark 10:6-12

But from the beginning of the creation, God made them male and female;

John 8:3-5

Then the scribes and Pharisees brought to him a woman caught in adultery; and placing her in the midst,

1 Timothy 5:11-14

But the younger widows reject: for when they give themselves to wantonness contrary to Christ, they will marry;

Treasury of Scripture Knowledge

Summary

So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man.

General references

Bible References

So then

Matthew 5:32
But I say unto you, Whosoever shall put away his wife, except on account of whoredom, causeth her to commit adultery: and whosoever shall marry her that is put away, committeth adultery.
Mark 10:6
But from the beginning of the creation, God made them male and female;
John 8:3
Then the scribes and Pharisees brought to him a woman caught in adultery; and placing her in the midst,

Though

1 Timothy 5:11
But the younger widows reject: for when they give themselves to wantonness contrary to Christ, they will marry;

General references

Mark 10:9
What therefore God hath yoked together, let no man separate.