One specific purpose for our life might be witnessing to others that God is the one responsible for producing the fruitful results of a life faithfully lived under even the most trying circumstances. To Him be the glory:
Don’t hide your light! Let it shine for all; let your good deeds glow for all to see, so that they will praise your heavenly Father. Matthew 5:15-16 TLB.
God can be trusted to lead us on the path He has chosen for us, if that is how we want to live our life. He has said it, and He will do it. That plan includes answering our sincere prayer to abide in us and we in Him each day, guiding us with His counsel and fulfilling His purpose for us for our life and for that day.
God fulfilled His purpose for Jesus’ life as described in one of the best known of all Bible verses:
For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. For God did not send his Son into the world to condemn the world, but to save the world through him. John 3:16-17
Just like David (Acts 19:36), Jesus did not die until his purpose for living was fulfilled:
When he had received the drink, Jesus said, “It is finished.” With that, he bowed his head and gave up his spirit. John 19:30
What a comfort and blessing it is to realize that not only does your life have a God-given purpose, but also that God will give you the strength, courage, and will to persevere until that purpose is fulfilled, then have you rest in peace,
...being confident of this, that he who began a good work in you will carry it on to completion until the day of Christ Jesus. Philippians 1:6