BhG 7.21

syntax

yaḥ yaḥ bhaktaḥ (whoever devotee) yām yām tanum (whichever form) śraddhayā (with faith) arcitum (to worship) icchati (he desires),
aham (I) tasya tasya [bhaktasya] (each devotee respectably) tām eva (just this) acalām śraddhām (steady faith) vidadhāmi (I grant).

grammar

yaḥ yaḥ	–	yat sn. 1n.1 m. – whoever (distributive use);
yām yām	–	yat sn. 2n.1 f. – whichever (distributive use);
tanum	–	tanu 2n.1 f. – thin, small; body, form (from: √tan – to spread out);
bhaktaḥ	–	bhakta (√bhaj – to share, to love, to rejoice, to worship) PP 1n.1 m. – distributed, divided, loved; worshipper, devotee, loving;
śraddhayā	–	śraddhā 3n.1 f. – with faith (from: śrat – in compounds: faith; √dhā – to put [faith]; śraddhā – faith, confidence);
arcitum	–	√arc (to worship) inf. – to praise, to worship, to adorn;
icchati	–	√iṣ (to desire) Praes. P 1v.1 – he desires;
tasya tasya	–	tat sn. 6n.1 m. – his respective (distributive use);
acalām	–	a-cala 2n.1 f. – motionless (from: √cal – to move, to shake, cala – moving, shaking);
śraddhām	–	śraddhā 2n.1 f. – faith (from: śrat – in compounds: faith; √dhā – to put [faith]; śraddhā – faith, confidence);
tām	–	tat sn. 2n.1 f. – this;
eva	–	av. – certainly, just, merely;
vidadhāmi	–	vi-√dhā (to divide, to grant) Praes. P 3v.1 – I grant;
aham	–	asmat sn. 1n.1 – I;

textual variants

bhaktaḥ → bhaktyā (with devotion);
icchati → acchati;
vidadhāmi → vyadadhāmi;
tām eva vidadhāmy aham → tasyāṁ tasyāṁ dadāmy ahaṁ (this and this I give);

Śāṃkara

teṣāṃ ca kāmināṃ—

yo yaḥ kāmī yāṃ yāṃ devatā-tanuṃ śraddhayā saṃyukto bhaktaś ca sann arcituṃ pūjayitum icchati, tasya tasya kāmino’calāṃ sthirāṃ śraddhāṃ tām eva vidadhāmi sthirīkaromi

Rāmānuja

tā api devatā madīyās tanavaḥ, „ya āditye tiṣṭhan … yam ādityo na veda yasyādityaś śarīram” ityādiśrutibhiḥ pratipāditāḥ / madīyās tanava ity ajānann api yo yo yāṃ yāṃ madīyām ādityādikāṃ tanuṃ bhaktaḥ śraddhayārcitum icchati; tasya tasyājānato ‚pi mattanuviṣayaiṣā śraddhety anusandhāya tām evācalāṃ nirvighnāṃ vidadhāmy aham

Śrīdhara

devatā-viśeṣaṃ ye bhajanti teṣāṃ madhye yo ya iti | yo yo bhakto yāṃ yāṃ tanuṃ devatā-rūpāṃ madīyām eva mūrtiṃ śraddhayārcitum icchati pravartate tasya tasya bhaktasya tat-tan-mūrti-viṣayāṃ tām eva śraddhām acalāṃ dṛḍhām aham antaryāmī vidadhāmi karomi

Madhusūdana

tat tad devatā-prasādāt teṣām api sarveśvare bhagavati vāsudeve bhaktir bhaviṣyatīti na śaṅkanīyaṃ, yato yo ya iti | teṣāṃ madhye yo yaḥ kāmī yāṃ yāṃ tanuṃ devatā-mūrtiṃ śraddhayā janmāntara-vāsanābala-prādurbhūtayā bhaktyā saṃyuktaḥ sann arcitum arcayitum icchati pravartate | caurādikasyārcayater ṇij-abhāva-pakṣe rūpam idam | tasya tasya kāminas tām eva devatā-tanuṃ prati śraddhāṃ pūrva-vāsanāvaśāt prāptāṃ bhaktim acalāṃ sthirāṃ viddadhāmi karomy aham antaryāmī, na tu mad-viṣayāṃ śraddhāṃ tasya tasya karomīty arthaḥ | tām eva śraddhām iti vyākhyāne yac-chabdānanvayaḥ spaṣṭas tasmāt pratiśabdam adhyāhṛtya vyākhyātam

Viśvanātha

te te devāḥ pūjāṃ prāpya prasannās teṣāṃ sva-sva-pūjakānāṃ hitārthaṃ tvad-bhaktau śraddhām utpādayiṣyantīti mā vādīḥ | yatas te devāḥ sva-bhaktāv api śraddhām utpādayitum aśaktāḥ | kiṃ punar mad-bhaktāv ity āha yo ya iti | yāṃ yāṃ tanuṃ sūryādi-deva-rūpāṃ madīyāṃ mūrtiṃ vibhūtim arcitum pūjayituṃ tām eva tat-tad-devatā-viṣayām eva, na tu sva-viṣayāṃ śraddhām aham antaryāmy eva vidadhāmi, na tu sā devatā

Baladeva

sarvāntaryāmī mahā-vibhūtiḥ sarva-hitecchur aham eva tat-tad-devatāsu śraddhām utpādya tāḥ pūjayitvā tat-tad-anurūpāṇi phalāni prayacchāmi, na tu tāsāṃ tatra tatra śaktir astīty āśayavān āha ya iti dvābhyām | yo ya ārtādi-bhakto yāṃ yām ādiyādi-rūpāṃ mat-tanuṃ śraddhayārcituṃ vāñchati | tasya tasya tām eva tat-tad-devatā-viṣayām eva, na tu mad-viṣayām | acalāṃ sthirām | vidadhāmy utpādayāmy aham eva, na tu sā sā devatā | śrutiś ca tat-tad-devatānāṃ mat-tanutvam āha ya āditye tiṣṭhaty ādityād antaro yamādityo na veda yasyādityaḥ śarīram [BAU 3.7.9] ity ādyā