Deuteronomy 22:22 defines adultery as “…lying with a woman married to an husband…”. Do not commit adultery is one of the Ten Commandments. From God's perspective, adultery is a work of the flesh and is bad as committing heresies and even murder. God considers adultery as an unrighteous act. Adultery starts in a person's heart and is a willful act no matter who is the tempter and who is tempted. See below for more commentary and scriptures on the definition of adultery.

Luke 8:13. Our unbelief in God is evident by the sin in our lives. Our unbelief can only be reversed by the word of God and our acceptance of Jesus Christ as our Savior. To continue growing in our faith we must continue to learn and be rooted in God's word. If we are not rooted in God's word, we will fall away into sin and unbelief again (Luke 8:13, “They on the rock are they, which, when they hear, receive the word with joy; and these have no root, which for a while believe, and in time of temptation fall away.”).

Genesis 3:1. The devil has no capability to do us direct harm. He can only do us harm by trickery. In Genesis 3:1 it says, "Now the serpent was more subtil than any beast of the field…". In the Garden of Eden the Devil did no direct harm to Adam and Eve. All he did was use his craftiness to confuse and tempt Adam and Eve to disobey God. Adam and Eve were not forced by the Devil to eat of the fruit. It was his craftiness that led them to sin.

James 1:12. Keeping a relationship with God is more than addressing the past sins in our lives. Fixing a broken relationship with God also means avoiding sin every day. Temptation is with us everyday, but God desires for us to avoid sin. We prove our love of God when we endure temptation. God rewards us who truly love Him (James 1:12, "Blessed is the man that endureth temptation: for when he is tried, he shall receive the crown of life, which the Lord hath promised to them that love him.")

Matthew 5:28. The definition of adultery includes the characteristic that it comes from within and it is not caused by outside influences. Adultery is committed by two willing partners. One person in the relationship may have been the temptress or tempter, but the other person accepted the temptation. Adultery is always birthed from our own heart. If you do not have adultery in your heart, you will not commit adultery no matter what the temptation. God knows that adultery starts in the heart and he considers us adulterers when we even think about committing adultery.

2 Peter 2:9. If you are in right relationship with God through Jesus Christ, you will not be tempted to sin. An example of a sin is to commit adultery. You can only effectively deal with any sin like adultery when you are in right relationship with God. Only the Lord can deliver you out of temptation (2 Peter 2:9, “The Lord knoweth how to deliver the godly out of temptations, and to reserve the unjust unto the day of judgment to be punished:”).

There is no adequate excuse when a person commits adultery or any sin.