The main lesson of Hosea's teaching is that God prefers steadfast love to sacrifice. Throughout the book of Hosea, God emphasizes the importance of a genuine, loving relationship with His people, rather than simply going through the motions of religious ritual. Hosea teaches that God desires our hearts more than anything else and that true worship involves not just external acts of sacrifice, but also internal acts of love and devotion to God. Therefore, the central message of Hosea's teaching is that God desires a deep and sincere love relationship with His people, rather than just outward religious practices.