The letters Alif and Lam before the word Hamd serve to encompass all types of thanks and appreciation for Allah, the Exalted. A Hadith stated,

«اللَّهُمَّ لَكَ الْحَمْدُ كُلُّهُ، وَلَكَ الْمُلْكُ كُلُّهُ، وَبِيَدِكَ الْخَيْرُ كُلُّهُ، وَإِلَيْكَ يُرْجَعُ الْأَمْرُ كُلُّهُ»

(O Allah! All of Al-Hamd is due to You, You own all the ownership, all types of good are in Your Hand and all affairs belong to You.)