I struggled for a long time when I was a newly born-again Christian. I just did not understand the thought that Jesus paid everything for us on the cross and yet, there was still work for us to do here on earth. After many years of seeking an answer, I finally got peace when I realized that the work that Jesus wants me to do is not onerous or demanding but rather loving and kind and merciful. The work He has given me to do is the same that He did on earth, i.e. to spread the good news of salvation through grace.
Seeing others believe in Christ builds my own faith. Helping others to come to know Christ as their Lord and Savior builds it even more and that is a living legacy worth having. God has given us all of the tools we need to share about Jesus in His Word. Some of us are better at using the Word than others, but all are supposed to be daily digging into the Word in order to share it with those who need it. The Bible is our spiritual food and just as you would not go days without eating (unless you are called to fast for a period of time), neither should any Christian go days without reading God’s Word and letting His Spirit speak to your heart. Then, once your own faith is built up by His Word inside you, then you can take what you have learned and share it with others. A hammer builds, but only in the hands of someone wielding it. Likewise, God’s Word saves but only from the mouths of those who speak it.