The Bible makes it plain and clear, you will never please God without faith. You cannot come to God without faith. You cannot walk with God without faith. Your prayers will not be answered without faith. How can we come to faith? We don't. Understand faith comes to us. Faith is the gift of God, that comes to us by the word of God. "So then faith comes by hearing, and hearing by the word of God" (Romans 10:17)
You may confess, I have faith, but my faith is weak. Understand faith may grow stronger or become weaker in your life. God gives to each one of us the measure of faith. The faith of God comes to us from the Lord Jesus Christ, through the Holy Spirit. Don't look to yourself to muster faith sufficient. It never works that way. Look to another, even our Lord Jesus Christ. God through Christ is the source of our faith. Keep your focus upon Christ. "Looking unto Jesus, the author and finisher of our faith" (Hebrews 12:2).
Understand what causes our faith to oscillate between stronger and weaker? Here is the key to greater faith. Understand that faith works through love. Faith never ever comes without love. They are bonded together and are completely inseparable. Focus upon love, even the love of God in Christ. Remember, "God is love" (1 John 4:8). Love gives faith. Love sustains faith. Greater love means greater faith. The key to faith is love, simply because God is love. "And now abide faith, hope, and love; but the greatest of these is love" (1 Corinthians 13:13).
When the believer is filled with the love of God, he will be filled with the Spirit of God. That results in being filled with the faith of God. The Holy Spirit is sensitive to what we do and say. When we sin against love, we quench the Spirit of God. That results in weaker faith. Love is the key to understand faith in God.