Well actually it’s impossible. It’s completely impossible apart from the work of God in our hearts. And exactly what does that work look like that enables us to imitate God? Well it really starts with the regenerating work of the Spirit. It’s impossible for us (in terms of who we are by nature) to be able to imitate God, because instead, as Jesus said, by nature, our father is Satan, and we imitate him. And so we have to be changed, radically changed at the heart level. And that’s what regeneration is; it’s God making us new, giving us, in the words of the prophet Ezekiel, a new heart.
Moreover, I will give you a new heart and put a new spirit within you; and I will remove the heart of stone from your flesh and give you a heart of flesh.Ezekiel 36:26
And so that has to happen first before we can ever think about being imitators of God. But in addition to that there also has to be the empowering and enabling of Jesus Christ our Lord. In talking about the fruit that we can demonstrate as His followers He says in John 15 apart from me, you can do nothing.
“I am the vine, you are the branches; he who abides in Me and I in him, he bears much fruit, for apart from Me you can do nothing.”– John 15:5
So there there’s no way that we can demonstrate the fruit of the Spirit – and in reality that’s being an imitator of God – apart from the enablement of Jesus Christ himself personally. We are in Him and we receive power from Him as if we were attached by some sort of a divine umbilical cord; so that also has to be there. But very practically before we can be imitators of God, there has to be the work of the Word. We have to understand from the Word itself what it looks like to be imitators of God. And apart from that, it’s not that we can imitate God in every way – we can’t be omnipresent – what Paul is talking about is imitating God in our moral characters. For example, we’re commanded to forgive like God forgives. Peter says we’re to be holy like God is holy.
…but like the Holy One who called you, be holy yourselves also in all your behavior; because it is written, “You shall be holy, for I am holy.”– 1 Peter 1:15-16
So in the moral attributes of God we can imitate God. And specifically in Ephesians 5. Paul says we’re to be imitators of God and walk in love.
Therefore be imitators of God, as beloved children; and walk in love, just as Christ also loved you and gave Himself up for us, an offering and a sacrifice to God as a fragrant aroma.– Ephesians 5:1-2
In other words were to imitate God, by loving like God loves. And the way to do that is really explained in the verses that preceded the end of Ephesians 4 where we’re told again and again what loving other people looks like. That’s what it means to imitate God