My sister-in-law is a very devout person most of the time, but she also gets upset fairly easily when things don't go her way, and then she doubts if God even cares about her. What can I suggest she do to have a more stable faith?
We all have an emotional side to us — and this isn’t wrong, because God gave our emotions to us, and they are an important part of our lives. The Bible includes such emotions as joy and peace among the spiritual fruit God wants to give us (see Galatians 5:22-23).
But emotions come and go — and when our faith is based only on our feelings, it becomes unstable and uncertain. In other words, if my faith is strong only when I feel good, what happens when I don’t feel good? Or what happens to my faith when life isn’t going the way I want it to? Then my faith wavers and grows weak. The Bible warns, “The one who doubts is like a wave of the sea,… double-minded and unstable in all they do” (James 1:6,8).
Encourage your sister-in-law to build her faith not on her feelings, but on facts — the fact of God’s unchanging love for her, and the fact of Jesus’ death and resurrection. This is why the most important thing she can do is set aside time each day to be alone with God — reading the Bible, praying, and meditating on the truths of His Word. Urge her to make this part of her life every day.
Our emotions come and go — but God never changes, and no matter how we feel or what is happening in our lives, our faith and trust must be in Him. “Trust in the Lord forever, for the Lord, the Lord himself, is the Rock eternal” (Isaiah 26:4).