Every Christian is a full-time Christian missionary and minister, regardless of the nature of work they do. We are all called to share the light and love of our wonderful Saviour with the lost people of the dark world.
People think they cannot and should not be in any direct mission work for God if they struggle with wilful, known sins.
Obedience to God is indeed necessary for a God-honouring Christian life and ministry. However, nobody is perfect. We all sin, whether the sin is considered big or small. There is no single Christian minister who never committed any wilful sin throughout his life, except perhaps Jesus. Whether it is anger, pride or irritation or procrastination or negligence or idle talk, we all sin wilfully, knowing that is a sin. Our sins may be different, but we all struggle with sin often and later regret it. The apostle Paul felt the same.
Now, should I wait until I get rid of all the so-called big sins I know before I could ever share the Gospel with someone or teach the Biblical truths to others? In that case, we are all going to wait forever. Nobody is ever going to be perfect on this side of heaven, but we are all supposed to be striving for perfection. The well-lived Christian life is a life of progression towards more Christ-likeness.
The devil is extremely intelligent and cunning. When you are tempted to sin, he tells you, "this sin is okay. Everybody does it". And when you try to do something good for God, he says, "You are unworthy to do this ministry or teach others because you committed that sin that day". Remind yourself of what God's Word tells you. When you are tempted to sin, you should say "No" and when you are prompted by the Holy Spirit to do something good, you should count yourself worthy, because God counted you worthy.
Genesis 3:1-11 - Now the serpent was more cunning than any beast of the field which the LORD God had made. And he said unto the woman, Yea, hath God said, You shall not eat of every tree of the garden?
Other posts you may be interested in: