We are so glad to join you in prayer, as you seek to rekindle your first love for God. This is a beautiful desire, and we know that God will be pleased with your yearning to draw closer to Him. Let us look at the scripture you mentioned, and consider the words of Jesus to the church in Ephesus:
Revelation 2:4 WEB "But I have this against you, that you left your first love."
It is so important to hold onto our love for God. We are to love the Lord our God with all our heart, all our soul, all our mind and all our strength. Let us pray together that your love for him be rekindled.
Heavenly Father, we come before you in the name of Jesus Christ, asking that you would help our dear brother/sister return to their first love for you. Revive their heart and captivate them again with your love.
Father, reveal yourself to them in a new and powerful way. Remind them of your mercy and let them experience the depth of your love. Let them be drawn to you and experience the love of Christ in a new and fresh way. In the name of Jesus Christ, we pray for them that they will be filled with the knowledge of your will in all wisdom and spiritual understanding.
Colossians 1:9-10 WEB "For this cause, we also, since the day we heard this, don’t cease praying and making requests for you, that you may be filled with the knowledge of his will in all spiritual wisdom and understanding, 10 that you may walk worthily of the Lord, to please him in all respects, bearing fruit in every good work and increasing in the knowledge of God;"
We know that when we focus on Jesus and His love for us, our own love for Him will grow. Remind our dear brother/sister of your goodness and faithfulness, and let them be drawn to you in a new and fresh way, and be filled with a desire to live lives worthy of You, pleasing You in every way, and bearing fruit. In the mighty name of Jesus Christ, we pray these things.
Lastly, let us encourage you to spend time in God's Word, in prayer, and in fellowship with other believers. As you draw near to God, He will draw near to you, and you will experience the joy and intimacy of a renewed first love for Him. May God bless you and guide you, as you seek Him with all your heart.