It is narrated from Sayyiduna Samurah bin Jundub (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The words most beloved to Allah, the Mighty and Majestic, are four: La ilaha illallah (there is no god but Allah), Allahu akbar (Allah is the Greatest), Subhanallah (glory be to Allah), and Alhamdulillah (all praise is for Allah). It does not harm you with which of them you begin."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6761