“A calling is a summons from God to a task that accomplishes His purposes.” There’s a lot of information packed into that sentence. So let’s “unpack” it.

A calling is a summons from God …”
When I was a boy I usually went outside to play after dinner. At dusk mom or dad would call out, “Time to come home.”  They expected me to come right away. When I arrived they gave me a task like “Go take a bath.” In the same way, someday God will summon you. As a believer you know His voice. When you hear it, go to Him in prayer and listen.

“… to a task …”
God has work for you to do - a mission just for you. He’s equipped you with everything you need to accomplish it. Your spiritual gifts play a big part in fulfilling your calling. Whatever the job is, don’t try to figure it out. God doesn’t work that way. He’ll reveal it in His appointed time. Wait for it. It’ll certainly come and will not be late. In the meantime, faithfully serve others.

“… that accomplishes His purposes.”
History is hurtling headlong to the Second Coming of Christ. You have between now and then to accomplish your work. Your assignment falls into one or both of these categories: evangelism and discipleship. In essence, your work is to tell people about salvation and to serve them in love.