On every occasion, you have to mould yourself according to the pledge of faith. You have to make yourself firm in faith every moment. Say that my Lord is God and remain steadfast, means to have faith in God and whenever any situation arises, don't deviate from the requirements of faith. Remain firm on your belief. This is the meaning of the hadith. For example, if you say I have faith in God.
A hadith says: قُلْ: آمَنْتُ بِاللهِ، ثُمَّ اسْتَقِمْ (Musnad Ahmad 15417) This hadith is no simple matter. When you discover God and you have accepted the truth, your test begins. In this world, you are being tested every moment. When a person has faith in God, his test begins.
In every situation, you will have to make a decision about the behaviour which is in accordance with belief in God and which behaviour is not in accordance with belief in God.
On every occasion, you have to mould yourself according to the pledge of faith. You have to make yourself firm in faith every moment. Say that my Lord is God and remain steadfast, means to have faith in God and whenever any situation arises, don't deviate from the requirements of faith. Remain firm on your belief. This is the meaning of the hadith. For example, if you say I have faith in God.
What does this mean? I will lead my life in this world just as God has laid down. What then? The Quran says: وَإِذَا مَا غَضِبُوا هُمْ يَغْفِرُونَ (42:37). When a believer gets angry, he forgives. What is the meaning of being steadfast on faith here? When in society, family or neighbourhood someone makes me angry, you should remember that it is God's command to forgive the person. This is the meaning of being steadfast. The Quran says: Fulfil your promises. (2:177) Remember this teaching whenever you have made a promise. This will be an enactment of remaining steadfast on faith.
In this way, in every turn of life, morning and evening, you face many situations where you can follow your desire or follow God. There are requirements of family and tradition, and there are also requirements of God and His Prophet. On every occasion, you should refrain from bowing down to the other requirements. Instead you should follow the path laid down by God. This is being steadfast on faith.