What is the source of Saptapadi Shlokas which are recited during Vivaha Sanskar?

Question

This answer to the question "What are the Saptapadi or the seven promises of marriage?" provides seven shlokas known as "SaptaPadi" and is said to be of great importance in Vivaha Sanskar.

त्‍वत्तो मेऽखिलसौभाग्‍यं पुण्‍यैस्‍त्‍वं विविधै: कृतै: ।
देव ! संपादितो मह्यं वधूराद्ये पदेऽब्रवीत्‌ ।।

IAST: t‍vatto me’khilasaubhāg‍yaṃ puṇ‍yais‍t‍vaṃ vividhai: kṛtai: |
deva ! saṃpādito mahyaṃ vadhūrādye pade’bravīt‌ ||

Translartion: O Lord! I have had the good fortune of acquiring you due to the various types of merits acquired by me in various births.

I have tried finding source/reference for these shlokas in text/scripture but the only references I found are blogs and articles and hence I would like to post this question.

The physical books which I have also gives the same shlokas but the citation is missing. So, Is there any reference for this shlokas in our scriptures e.g Brahman Granthas or Grihya Sutras?

Answer 1

The source for the Saptapadi Mantras can be found in 3 of the Gṛhya-sūtras

a.Āśvalāyana-gṛhya-sūtra of the Rig Veda

b.Paraskara-gṛhya-sūtra of Shukla Yajur Veda

c.Sakhayana-gṛhya-sūtra of the Rig Veda

a.

Translation: He then causes her to step forward in a northeastern direction seven steps with (the words), 'For sap with one step, for juice with two steps, for thriving of wealth with three steps, for comfort with four steps, for offspring with five steps, for the seasons with six steps. Be friend with seven steps. So be thou devoted to me. Let us acquire many sons who may reach old age!'
Āśvalāyana-gṛhya-sūtra I.7.19

b.

Translation: 1. Then he makes her step forward in a northern direction seven steps (with the words),'One for sap, two for juice, three for the prospering of wealth, four for comfort, five for cattle, six for the seasons. Friend! be with seven steps (united to me). So be thou devoted to me. 2. (The words), 'May Viṣṇu lead thee' are added to every part (of the formula). ~Paraskara-gṛhya-sūtra I.8.1,2

c.

Translation:5. (The Ācārya) makes (them) step forward in a north-eastern direction seven steps (with the words),6. 'For sap with one step, for juice with two steps, for the prospering of wealth with three steps, for comfort with four steps, for cattle with five steps, for the seasons with six steps. Friend be with seven steps.' ~ Sakhayana-gṛhya-sūtra I.14.5,6

Source for this can be found here

NOTE: a. In accordance to the answer written Pandya ji here, I think the modern day mantras seem to have been derived from the Grhya-sutras (as their meaning is still the same).

b. Also after trying to the best of my abilities i only found the verses for vows taken by the groom, but could not find for vows taken by the bride.If i come across them i will update the answer accordingly.