This is a situation that need not exist. We all have tried witnessing to our natural family ie. mom, dad, brothers and sisters, and we can all relate to the way Jesus felt when he returned to His hometown and so the resistance He faced from those that have known Him all His life. The hardest thing any believer will ever face is witnessing within the family.
Friends, aquaintances and strangers are all by comparison relatively easy. For the most I believe it is because of a vested interest. Friends will come and go and the father away a person is to you personally, the easier it becomes to deal with rejection. Family on the other hand is highly vested. You love them and would do anything to protect them. When they reject your witness it hurts very badly. Face it, you want your natural family to be pert of the Church family.
Your Church or eternal family, even when you disagree or fight, you know they are part of your family forever and you are part of theirs. It becomes, as you grow in faith and the strength to apply that faith, easier to opt to spend more and more time and energy on the family you will never lose. Often times this results in neglect or distance with your natural family that remain of the world. The natural family loves you but they do not affirm you, your choice or your Lord. They are in many cases outright hostile to all of that.
To this end I have developed some tactics that have work for me. That doesn't mean they will work for you or that they won't.
First, witness to them yourself BUT do so hoping for the best, wholehearted acceptance of the Lord, but expect the worst, outright rejection.
Second, always be in prayer for them. The Lord will back you up and support you when you call on Him. There is never a time when "going it alone" is necessary for the believer.
Third, recruit a helper. This for me has been a family friend that shares a place in God's family. They have a sense of distance so can focus on the evangelistic work without the intimate pain caused by rejection. It still hurts them no doubt but not nearly to the same degree it will hurt you.
Forth, live your faith openly and with joy. Most, I hope, have read the classic Tom Sawyer. In the novel Tom is tasked to paint a fence. He doesn't want to do it and notices his friends watching and knows they don't want to do it either. So Tom makes it look like he is having a blast painting that fence. His joy, which is visable attracts his friends and he is then able to tell them about how much fun it is. His friends eventually want to try it themselves. While Tom used it to get out of the work, we as believers should use it to get them to join into the work. That is to become partners in service. At the end Tom's friends really did have a good time painting. As followers of christ, we know that if someone will commit to the Lord, they will know true joy in all circumstances, even if it can be best viewed in hindsight. Basically, it is up to us to make living for Christ attractive by our life's example. This will re-enforce what is taught by the one you recruited for help in witnessing.
Fifth, know the Scriptures. As your family becomes interested they will likely come to you because you are there. Answer honestly and be willing to admit when you don't know the answer. Make it clear that just because you don't know the answer right now doesn't mean there isn't an answer. Also, when you don't know, seek one that does. Never leave a seeker hanging.
Our goal is not to neglect our natural family for the eternal family but rather to join the two. While salvation is of the Lord, we still have a part to play and play it we must. Love both families but in doing so show, through your life, that being in God's family is the place your natural family should most desire to be. This road we have decided to walk is often hard and rocky from our perspective but has been trod by no less than Jesus himself. He has blazed the trail ahead of us so that we may follow Him. Do not dispare and do not give up but always, with great joy, keep moving forward doing all the Lord has set before you to do.
In Christ,
Bishop SEH