Eph 2:1-3 is about being quickened from spiritual death. Before people are saved, they are dead in trespasses and sins.  According to Rom 5:12, this death came as a result of Adam’s transgression against Gen 2:17.  When Adam and Eve ate from the tree of the knowledge of good and evil, everything about them was affected by death.  And so, everything about us was also affected by death.  This is our spiritual death.

In Lk 9:59-60, Jesus told a prospective disciple, who wanted to wait until he had buried his father before following Jesus, “Let the dead bury the dead”.  Being dead in trespasses and sins is a spiritual condition that results in physical death and ultimately eternal death in the lake of fire for those who aren’t saved, Rom 6:23, Rev 21:8.

This spiritual death in us affected three main areas of our being.  And it requires us being quickened from spiritual death to overcome these affects, Jn 3:5-8.  Our spiritual death:

Quickened from spiritual death affects our walk – Eph 2:2.

• We walked according to the course of this world – the course of this world is contrary to God Jn 1:10; Jn 15:18.  Gal 1:4 says, “Who gave himself for out sins, that he might deliver us from this present evil world.”  This world is heading to its terrible end in Matt 24:35.  Therefore, when we are saved, we must not love the world or befriend the world, 1 Jn 2:15-17, Jas 4:4.  Notice our walk was “in time past”.  We shouldn’t be walking that way anymore.  We are quickened from spiritual death.
• We walked according to the prince of the power of the air – in Jn 14:30, Jesus said, “the prince of this world cometh, and hath nothing in me”.  He is the god of this world and is opposed to the gospel of Jesus Christ, 2 Cor 4:3-4.  After we are saved, he is our adversary Eph 6:11-12.  He is the spirit that now worketh in the children of disobedience.  So there is a spirit in this world that will not obey God.  This explains why you see so much wickedness in the world and why we must be saved, 1 Jn 5:18-19.  You shouldn’t be living like the devil now, as you did “in time past”.

Affects our conversation – Eph 2:3.

Our conversation was in the lusts of our flesh.  Our conversation is our behavior, not just our communication, Eph 4:22.  Our old man is corrupt according to the deceitful lusts.  Now that we’re saved, our conversation should be in heaven, Phil 3:20.  We have been quickened from spiritual death.

• We fulfilled the desires of the flesh – we did what our flesh wanted us to do. There is nothing good about our flesh [Rom 7:18].  The evil you are seeing in the world right now is simply an expression of “them that walk after the flesh in the lust of uncleanness,” [2 Pet 2:10].  Follow Paul’s instructions, “Walk in the Spirit, and ye shall not fulfill the lust of the flesh,” Gal 5:16-17.
• We fulfilled the desires of the mind – sin often starts in the mind Eph 4:17-19.  Prov 23:6-7 says, “as he thinketh in his heart so is he”.  Thus, we must war against our imaginations, 2 Cor 10:4.  Thankfully, we now have the mind of Christ, 1 Cor 2:16.

Affects our nature – Eph 2:3.

We were by nature the children of wrath, even as others.  David said, “Behold, I was shapen in iniquity, and in sin did my mother conceive me,” [Ps 51:5].  We are sinners at the very core of our being, Mk 7:21-23.  Thus, our old man must die Rom 6:6, and we must live unto God through Jesus Christ and walk in newness of life, Rom 6:5, 11.  We must be transformed.  When a person says, “I was made this way” to justify their sin, they are partly telling the truth.  However, they don’t have to remain that way.  As a new creature in Christ, they can and should change.  They have been quickened from spiritual death.

Conclusion: when we are quickened from spiritual death by the Lord in salvation, we should start walking his way, not the world’s way; our conversation should fulfill the will of the Lord and not the desires of our flesh and mind; and our nature should die with Christ so that we may be transformed as a new creature in Christ.