Hacham Ben Sion Abba Shaul, in his work Or Le’sion (vol. 2, p. 291), addresses the case of one who meets somebody to whom he is obligated to show honor just before he enters the synagogue. This would include his father, father-in-law, grandfather, older brother, an elderly person and a Torah scholar. In such a case, the question arises as to whether or not one is required to allow the other person to enter the synagogue first. There is an important Misva to be among the first ten men in the synagogue, and an even greater Misva to be the first person in the synagogue. Should one forego on this Misva in order to show respect to his father (or the other people mentioned above), or does the Misva to be the first person in the synagogue take precedence?
Hacham Ben Sion rules that even in this case one must show respect to his father and allow him to enter the synagogue first. Honoring one’s parents is an outright Halachic obligation ("Hiyub Gamur"), while being the first in the synagogue is a very worthwhile Misva, but not a strict obligation. Hence, one may not forego on his father’s honor for the purpose of fulfilling the Misva of entering the synagogue first.
Another interesting issue that arises with regard to honoring one’s father in the synagogue has to do with Misvot that are "auctioned" to the congregants. The Kanhag (Rav Haim Banbenishti, Turkey, 1603-1673) records an incident where the honor of reciting the Beracha over the Lulab was auctioned in the synagogue, and a man bid for this Misva on behalf of Rav David Hakohen, a distinguished Rabbi. The Kanhag also sought to purchase this Misva, and placed a higher bid. People questioned why this was permissible, as it seemed disrespectful to the other Rabbi, on whose behalf the man sought to purchase this Misva. The Kanhag explained that performing a Misva overrides the concern for the Rabbi’s honor, and it was therefore appropriate to offer a higher bid for the Misva even against a bid made on behalf of a prominent Rabbi.
Hacham Yishak Yosef, in his Yalkut Yosef (Honoring Parents, p. 363), cites some authorities who extend the Kanhag’s ruling to a situation of bidding against one’s father. According to these views, one may offer a bid in the synagogue for an Aliya or other Misva even against the bid made by his father, as the concern for one’s own Misva performance takes precedence over the concern for honoring his father. Others, however, maintain that one should not seek to outbid his father, even for the purpose of a Misva. Halacha follows the second view. If a son has the means to offer a higher bid than his father in the synagogue, then he should make a bid to purchase the Misva on behalf of his father, in order to give him honor.
Summary: If a son meets his father before entering the synagogue, he should allow his father to enter first, even if this will prevent him from being the first – or among the first ten – men in the synagogue. When a Misva is auctioned in the synagogue, a person should not bid a higher amount than his father, unless he seeks to purchase the Misva on his father’s behalf.
