Allah, exalted is He, commands gratitude towards parents after gratitude to Himself. But the teacher is the ‘parent’ about whom Imam al-Ghazali remarked, may Allah be pleased with him, that whereas biological parents save one from the fires of this world such a teacher saves one from the Fire of the next world.
A profound failing is not to acknowledge such teachers – I don’t mean teachers of information and sciences, but those beings who transmit behaviour, real life skills and much more profound matters.
It is a serious defect in a scholar of hadith to omit someone from his chain of transmission but to acknowledge their teacher’s teacher or teachers. This is called tadlees. Remarkably Ian Dallas/Shaykh Dr. Abdalqadir as-Sufi has suffered a great deal of this from some of his former students who have gone on to considerable renown on their own behalf without acknowledging him, without a single complaint on his part. This is a matter that needs redress.