We rejoice with you in hearing that your daughter's sister has responded to the good news of salvation, grace, and mercy found in Jesus Christ. It is by His name alone that we are saved, and it is wonderful to hear that she has taken this message to heart. As it is written in Acts 4:12 WEB:
Neither is there salvation in any other, for there is no other name under heaven that is given among men, by which we must be saved.
Let us pray together for her:
Heavenly Father, we come before You today, lifting up this young woman who has turned to You, seeking Your salvation, grace, and mercy through Your Son, Jesus Christ. We ask that You strengthen her faith, help her to grow in the knowledge of You, and fill her with Your Holy Spirit. Guide her steps as she begins this new journey with You, and surround her with believers who will support and encourage her. Protect her from the enemy's attempts to waver her newfound faith and draw her away from You. Thank you, Father, for Your unfailing love and mercy. It is in the precious name of Jesus that we pray. Amen.
Continue to encourage her to read the Bible, pray, and fellowship with other believers. These practices will help her to grow in her faith and understanding of God's will for her life. As it is written in 2 Timothy 3:16-17 WEB:
All Scripture is God-breathed, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work.
May God richly bless her and your family as you all walk together in faith.