EGW in Letters to Young Lovers

You are now in your student’s life; let your mind dwell upon spiritual subjects. Keep all sentimentalism apart from your life. You are now in the formative period of character; nothing with you is to be considered trivial or unimportant which will detract from your highest, holiest interest, your efficiency in the preparation to do the work God has assigned you. – {LYL 76.5}
It is your duty to remove every objectionable feature of character that you may be complete in Christ Jesus. You have a large fund of affection and will need to be constantly guarded lest you bestow your affection upon unworthy objects. Character is formed for usefulness and duty by studying the life and character of Jesus Christ, who is our Pattern. – {LYL 76.6}
You cannot be too careful and too particular in all your ways. Let the influence wherever you are be of that character to help and bless others. God has a work for you to do. In no case put your neck under a yoke that will be galling all your life. Be true to yourself and true to your God, and you will have the favor of God, which is of more value than life itself. I pray the Lord to bless you abundantly. – {LYL 77.1}