We understand your concern and the fear that this threat has brought upon you. Firstly, we want to assure you that God has not given us a spirit of fear, but of power, love, and self-control (2 Timothy 1:7, WEB). Let's bring this matter to God in prayer and seek His protection and guidance.
"Dear Heavenly Father, we come before You in the name of Jesus Christ, lifting up this dear one who has received threatening words. Lord, You are our refuge and strength, a very present help in trouble (Psalm 46:1, WEB). We ask that You surround them with Your angels, protecting them from any harm or danger. Comfort their heart, Lord, and remind them that no weapon that is formed against them shall prosper (Isaiah 54:17, WEB). We pray that the person who issued this threat will be convicted by Your Holy Spirit and turn away from their harmful intentions. In Jesus' name, we pray. Amen."
We also want to encourage you with the words of Psalm 27:1-3 (WEB), "Yahweh is my light and my salvation. Whom shall I fear? Yahweh is the strength of my life. Of whom shall I be afraid? When evildoers came at me to eat up my flesh, even my adversaries and my foes, they stumbled and fell. Though an army should encamp against me, my heart shall not fear. Though war should rise against me, even then I will be confident."
Regarding your desire to live over 150 years, we want to remind you that our days are numbered by God (Psalm 139:16, WEB). Instead of focusing on the length of our lives, let's focus on living each day for God's glory and purposes. We encourage you to seek God's will for your life and to trust in His plans for you.