The best of you are my generation, then those who follow them, then those who follow them

The best century and generation in the entire span of the world's history is the century in which the Prophet (may Allah's peace and blessings be upon him) and his Companions lived. It is mentioned in Sahīh Al-Bukhāri that he (may Allah's peace and blessings be upon him) said: "I was sent in the best centuries of the children of Adam, one century after another, until I was in the century in which I was."
Ibn Hajar said: This Hadīth implies that the Companions are superior to the Tābi‘is, and the Tābi‘is are superior to the followers of the Tābi‘is. However, is this superiority in reference to the group as a whole or to individuals? This is a matter of discussion, but the majority are inclined to the latter.
This refers to the necessity of adhering to the way of the first three generations, as those whose time was closer to the time of prophethood are more deserving of merit, knowledge, and emulation in following the guidance of the Prophet (may Allah's peace and blessings be upon him).
A vow: It is the obligation that a legally competent person imposes upon himself to perform an act of obedience not made obligatory by the Legislator, expressed through any statement indicating such an intention.
Condemnation of betrayal, failure to fulfill vows, and attachment to worldly life.
Condemnation of testifying without being called to give testimony, if the rightful claimant is aware of it. However, if he is unaware, it falls under the statement of the Prophet (may Allah's peace and blessings be upon him): "Shall I not tell you about the best of witnesses? The one who comes forward with his testimony before being asked for it." [Narrated by Muslim]