A vicar once came across a man working in his front garden.
"What a beautiful result there can be when God and man work together," the vicar said.
"True," replied the man. "You should have seen the state it was in before I gave God a hand."
Growing anything in the garden or the fields, or even raising a family, involves both us and God working together. As St. Paul wrote, "I planted, Apollos watered, but God gave the growth." Only God can supply life, and only God can provide the raw materials and energy we need to do anything. He has designed our life on earth so that whatever we do, it is in cooperation with him. The gardener was right in implying that God required his help in order to produce the beautiful garden that the vicar admired. That was how God wanted things to be.
The same thing is true for the growth of God's kingdom. He has entrusted to those of us who know him the task of sharing the good news of salvation and eternal life with others. "How can they hear without a preacher?" Paul asked. Even though God went to the extent of living among us on earth in the person of Jesus and dying a horrible death so that he could rise again and prove that death can be conquered and that we can live forever; even though God has done all that, the next generation will never know about it unless they're told by men and women like you and me. Thankfully of course there are Bibles and other ways in which people can learn the truth, but most people learn to know Jesus through personal contact with Christians who know him themselves.
Our personal growth into the likeness of Christ is a further matter of cooperation between the Holy Spirit and ourselves. On the one hand the Bible tells us that it is God who makes us holy, who sanctifies us, who changes us into the image and likeness of Jesus Christ. "I am the Lord who sanctifies you" (Leviticus 20.8). "God is at work in you, both to will and to work for his good pleasure," wrote Paul (Philippians 2.13). He does this through his Spirit coming to live within us. "From all your idols I will cleanse you... I will put my spirit within you, and cause you to walk in my statutes and be careful to observe my ordinances" (Ezekiel 36: 25,27). The fruit of the Spirit is love, joy, peace and so on, characteristics that the Spirit grows within us when we open up our lives to his presence.
But on the other hand we have an essential part in this growth too. The letter to the Hebrews tells us to "strive for the holiness without which no one will see the Lord". Peter tells us, "As he who called you is holy, be holy yourselves in all your conduct," (1 Peter 1.15). "Resist the devil, and he will flee from you," (James 4.7). Just as the gardener plants seeds and God makes them grow, so we have to plant the seed of God's word in our minds and hearts and God will cause it to grow. Jesus prayed for his disciples, "Sanctify them in the truth: they word is truth." The deeper we get God's word into our mind and heart the sooner his Spirit will produce in us the fruit of a holy, Christ-like life.
Sometimes we have to go through hard times for God to change us for the better. In 2013 and 2014 my wife Ann was twice hospitalized for many months with a very serious mental illness. She has since fully recovered and is now very different - less anxious, more patient, less self-centred and more loving. She has a stronger faith than ever. Hebrews says that even Jesus was made perfect through suffering (Hebrews 2.10). No wonder James tells us, "Count it all joy, my brethren, when you meet various trials, for you know that the testing of your faith produces steadfastness... that you may be perfect and complete" (James 1:2-4). Successfully enduring hard times and suffering needs faith in God. Both salvation and sanctification depend on faith. The Lord commissioned Paul to preach the good news to both Jews and Gentiles, "that they may receive... an inheritance among those who are sanctified by faith in me." (Acts 26:18)
There is one final way in which I think that our cooperation with God is really important, and that is in prayer. Why did Jesus tell us to pray, "Thy kingdom come, thy will be done on earth as it is in heaven," if God plans to establish his kingdom anyway; if he wants his will to be done on earth and can do whatever he wants?" Why do we have to pray for that to happen? It's because it's like everything else in this life that God has made: he wants it to be something that happens in cooperation with us. There is a worldwide spiritual battle going on, God and the devil fighting for our souls, and we are part of God's army, restraining and overcoming the work of Satan through our prayers. This is really important. It may be that one day when you meet the Lord face to face and you ask him, "Did you really listen to my prayers? Did they really make any difference?" then he will reply, as that gardener replied, "Well, you should have seen how things would have been if you hadn't helped me with your prayers."